Microelectromechanical system with non-collinear force compensation

ABSTRACT

A microelectromechanical system is disclosed that constrains the direction of a force acting on a first load, where the force originates from the interaction of the first load and a second load. In particular, the direction of a force acting on the first load is caused to be substantially parallel with a motion of the first load. This force direction constraint is achieved by a force isolator microstructure that contains no rubbing or contacting surfaces. Various embodiments of structures/methods to achieve this force direction constraint using a force isolator microstructure are disclosed.

FIELD OF THE INVENTION

[0001] The present invention generally relates to the field ofmicroelectromechanical systems and, more particularly, to amicroelectromechanical system that constrains the direction of forcesacting on a load in a manner such that there is also a reduced potentialfor rubbing or contact between different portions of the system.

BACKGROUND OF THE INVENTION

[0002] There are a number of microfabrication technologies that havebeen utilized for making microstructures (e.g., micromechanical devices,microelectromechanical devices) by what may be characterized asmicromachining, including LIGA (Lithographie, Galvonoformung,Abformung), SLIGA (sacrificial LIGA), bulk micromachining, surfacemicromachining, micro electrodischarge machining (EDM), lasermicromachining, 3-D stereolithography, and other techniques. Bulkmicromachining has been utilized for making relatively simplemicromechanical structures. Bulk micromachining generally entailscutting or machining a bulk substrate using an appropriate etchant(e.g., using liquid crystal-plane selective etchants; using deepreactive ion etching techniques). Another micromachining technique thatallows for the formation of significantly more complex microstructuresis surface micromachining. Surface micromachining generally entailsdepositing alternate layers of structural material and sacrificialmaterial using an appropriate substrate which functions as thefoundation for the resulting microstructure. Various patterningoperations (collectively including masking, etching, and mask removaloperations) may be executed on one or more of these layers before thenext layer is deposited so as to define the desired microstructure(s).After the microstructure(s) has been defined in this general manner, thevarious sacrificial layers are removed by exposing the microstructure(s)and the various sacrificial layers to one or more etchants. This iscommonly called “releasing” the microstructure(s) from the substrate,typically to allow at least some degree of relative movement between themicrostructure(s) and the substrate. The etchant is biased to thesacrificial material to remove the same at a greater rate than thestructural material. Preferably, the microstructure(s) is releasedwithout allowing the etchant to have an adverse impact on the structuralmaterial of the microstructure(s).

[0003] Microelectromechanical systems are typically actuated in a mannerwhere the direction of the load forces are substantially collinear withthe motion of the actuator. However, for some actuation systems, theload may be permitted to move in a path that is not collinear with themotion of the actuator (e.g., where the load moves out of plane).Off-axis forces (i.e., non-collinear) can result that can be detrimentalto the operation of the actuator. For instance, actuator electrodes mayshort together or portions of the actuator may contact other surfaces ofthe microelectromechanical system, thereby adversely impacting themotion of the actuator. It would be desirable for the portion the loadforce that is transmitted to the actuator to be constrained to be atleast substantially collinear with the motion of the actuator, therebyfacilitating the proper operation of the actuator. In other words, itwould be desirable for off-axis components of the load force to beisolated from the actuator by a force isolation system of sorts, orequivalently, by some way of constraining the direction of the forceacting on the actuator. For most applications, and particularly forapplications involving precise positioning of optical elements, it wouldbe further desirable to provide this force isolation function in amanner that does not exhibit hysteretic behavior. This generally meansthat it would be desirable for none of the surfaces of such a forceisolation system to come into contact or rub during normal operation ofthe microelectromechanical system.

BRIEF SUMMARY OF THE INVENTION

[0004] A primary object of the present invention is to at least attemptto minimize off-axis forces of a load acting on a given microstructure,and do so in a way that does not produce rubbing or contacting surfaces.In one application of the present invention, the noted microstructure isan actuator. In this case, the present invention enables precisepositioning of optical elements that involve out-of-plane motion,without exhibiting hysteretic behavior.

[0005] A first aspect of the present invention is embodied by amicroelectromechanical system that may be characterized as having afirst load microstructure and a second load microstructure that areinterconnected by a coupling assembly microstructure. Both the first andsecond load microstructures are each movably interconnected with asubstrate on which the microelectromechanical system of the first aspectis being fabricated, with the first load microstructure being movablerelative to the substrate along a first path. Movement of at least oneof the first and second load microstructures relative to the substrateexerts at least one force on the coupling assembly microstructure thatis not collinear with the first path along which the first loadmicrostructure moves relative to the substrate. Themicroelectromechanical system of the first aspect is configured toaddress this situation in at least two respects. One is that themicroelectromechanical system of the first aspect is configured toredirect the application of such a force to the first loadmicrostructure so as to be at least generally collinear with the firstpath along which the first load microstructure moves relative to thesubstrate. Another is that the microelectromechanical system of thefirst aspect is configured such that no portion of the coupling assemblymicrostructure is deflected by such a non-collinear force into contactwith any other portion of the microelectromechanical system, andincluding the substrate.

[0006] Various refinements exist of the features noted in relation tothe subject first aspect of the present invention. Further features mayalso be incorporated in the subject first aspect of the presentinvention as well. These refinements and additional features may existindividually or in any combination. A “load microstructure” in thecontext of the first aspect encompasses any microstructure that candeliver a force, be acted upon by a force, or both. Amicroelectromechanical actuator is typically a structure that candeliver a force in one or more directions in response to an appliedexternal signal or in response to a change in an applied externalsignal. Representative external signals include current, voltage ormagnetic fields. In addition, a microelectromechanical actuator can beacted upon by a force. As such, a microelectromechanical actuator itselfappears as a load to the structure on which it is acting in amicroelectromechanical system. Therefore, one or both of the first andsecond load microstructures in the case of the first aspect may be amicroelectromechanical actuator.

[0007] The force that acts on the coupling assembly microstructure as aresult of its interconnection with the first and/or secondmicrostructure may be of any appropriate type, from any appropriatesource, and used for any appropriate purpose. For instance, the forcethat is exerted on the coupling assembly microstructure by the firstand/or second load microstructure may be used to accelerate ordecelerate a mass, or may be the result of any such acceleration ordeceleration. Each force that is exerted on the coupling assemblymicrostructure by the first and/or second microstructure may be anactuated or active force (e.g., as a result of a control signal or achange in a control signal), a passive force (e.g., a stored springforce or the like), an inertial force, or any combination thereof.

[0008] The first load and/or second microstructure may include at leastone actuator. That is, the first and/or second load microstructures mayinclude a single actuator or multiple actuators that exert a concertedor collective force (directly or indirectly) on the other of the firstand second load microstructure through the coupling assemblymicrostructure. Any appropriate type of an actuator may be utilized asthe first and/or second load microstructure, including withoutlimitation an electrostatic comb actuator, a thermal actuator, apiezoelectric actuator, a magnetic actuator, and an electromagneticactuator. Control of the movement of any actuator utilized as the firstand/or second load microstructure may be accomplished in any appropriatemanner. In one embodiment, the signal that is used to control themovement of any such actuator originates external to themicroelectromechanical system. Both open loop and closed loopconfigurations may also be used for controlling the operation of anysuch actuator. Movement of any such actuator may be active (e.g., as aresult of the application of or a change in an external signal thereto),passive (e.g., utilizing a stored spring force or the like), or acombination thereof.

[0009] The movement of the first load microstructure and/or the secondload microstructure relative to the substrate in the case of the firstaspect may be either an actuated or a responsive movement. For instance,an actuated movement of the first load microstructure may result in themovement of the second load microstructure, or vice versa. Consider thecase where the first load microstructure is one or more actuators thatexert a force on the second load microstructure (through the couplingassembly microstructure) to induce a movement of the second loadmicrostructure. This movement of the second load microstructure may befor any relevant purpose and/or any relevant application. For instance,the second load microstructure may be a reflective microstructure (e.g.,a mirror) for providing any appropriate function. One appropriatefunction would be optical, including without limitation using thereflective microstructure to reflect an optical signal, change thedirection of an optical signal, change the focus of an optical signal,attenuate an optical signal, diffract an optical signal, or anycombination thereof. Any such reflective microstructure may beinterconnected with the substrate in any appropriate manner, includingwithout limitation directly by pivotally interconnecting the reflectivemicrostructure with the substrate utilizing one or more compliantmembers, indirectly by pivotally interconnecting an appropriatelyconfigured elevator with the substrate (an appropriate lever, includingwithout limitation, one or more levers or lever-like structures that arepivotally interconnected with the substrate so as to be movable at leastgenerally away from or toward the substrate), or a combination thereof(e.g., by interconnecting one or more portions of the reflective withthe substrate with one or more compliant members or flexures, and alsoby interconnecting one or more other portions of the reflectivemicrostructure with an elevator). “Pivotally interconnecting” or thelike, as used herein, means any type of interconnection that allows amicrostructure to at least generally undergo a pivoting or pivotal-likemotion when exposed to an appropriate force, including withoutlimitation any interconnection that allows a microstructure or a portionthereof to move at least generally about a certain axis. Representativepivotal interconnections include the use of a flexing or elasticdeformation of a microstructure or a portion thereof, as well as the useof relative motion between two or more microstructures that aretypically in interfacing relation during at least a portion of therelative movement (e.g., a hinge connection; a ball and socketconnection).

[0010] The coupling assembly microstructure utilized by the first aspectmay be of any relevant configuration, may include one or moremicrostructures, and broadly encompasses the entirety of the structuralinterconnection that extends between the first and load microstructures.The above-noted elevator could be considered as being part of thecoupling assembly microstructure, with the reflective microstructurethen being considered as the second load microstructure. However, theelevator and the reflective microstructure interconnected therewithcould be viewed as collectively defining the second load microstructure.In this case the coupling assembly microstructure could include anelongate coupling or tether that is interconnected (directly orindirectly) with both the first load microstructure (one or moreactuators) and the elevator. Other microstructures that may be includedin the coupling assembly microstructure include a pivotless compliantmicrostructure that will be discussed in more detail below. In oneembodiment, the first load microstructure is one or more actuators andthe coupling assembly microstructure includes a pivotless compliantmicrostructure and an elongate tether. The actuator(s) is appropriatelyinterconnected with an input section of the pivotless compliantmicrostructure, the tether extends between and interconnects an outputsection of the pivotless compliant microstructure with the notedelevator, and the noted reflective microstructure is appropriatelyinterconnected with a portion of the elevator that is able to move atleast generally away from or toward the substrate, depending on thedirection of motion of the actuator(s). In one embodiment, the tether inthis configuration is stiff so as to not buckle, flex, or bow to anysignificant degree when exposed to the magnitudes of external forcesthat would be exerted on the tether during normal operation of themicroelectromechanical system. As such, no significant amount of energywill be stored in the tether in this instance, which enhances thecontrol of the positioning of the reflective microstructure and allowsfor increased switching speeds.

[0011] The motion of one or more of the first and second loadmicrostructures relative to the substrate in the case of the firstaspect may be along any appropriate path, including without limitation alinear path, an arcuate path, a combination of one or more linear andarcuate path segments, or along a path that is defined by anyappropriate function (e.g., a polynomial). Moreover, the movement of oneor more of the first and second load microstructures may be in anyorientation relative to the substrate, including without limitation atleast generally parallel with the general extent of the substrate (e.g.,at least substantially horizontal), at least generally toward thesubstrate, at least generally away from the substrate, or anycombination of these types of movements.

[0012] In one embodiment, the first and second load microstructures areformed at the same elevation or level by surface micromachining in thecase of the first aspect (e.g., located the same distance from thesubstrate in at least one state). In another embodiment, the first andsecond load microstructures are formed at different elevations or levelsby surface micromachining in the case of the first aspect (e.g., locateda different distance from the substrate in at least one state). Themovement of the first load microstructure relative to the substrate maybe of any type in relation to the movement of the second loadmicrostructure relative to the substrate, so long as the movements areat least at some point in time not collinear. For instance, the firstand second load microstructures may move along parallel paths,regardless of which level/elevation such microstructures are formed inor otherwise occupy in the microelectromechanical system of the firstaspect. The first and second load microstructures may also move alongnon-parallel paths, regardless of which level/elevation suchmicrostructures are formed in or otherwise occupy in themicroelectromechanical system of the first aspect. Another option is forone of the first and second load microstructures to move relative to thegeneral lateral extent of substrate at least generally parallel thereto(i.e., an “in plane” motion) and for the other of the first and secondmicrostructures to move at least generally away from or toward thesubstrate (i.e., an “out-of-plane” motion), regardless of whichlevel/elevation such microstructures are formed in or otherwise occupyin the microelectromechanical system of the first aspect.

[0013] One way in which the force redirection function associated withthe first aspect may be addressed (the “first condition”) at least inpart is through the use of one or more doubly clamped beams. One or moredoubly clamped beams or the like may be attached to one or moreappropriate portions of the coupling assembly microstructure to limitthe amount of vertical movement of the same relative to the substratewhen exposed to a vertical force component, which in turn reduces themagnitude of the vertical force component that is ultimately transmittedto the first load microstructure. Doubly clamped beams aremicrostructures that are anchored to the substrate at least at onelocation on each side of the portion of the coupling assemblymicrostructure to which the given doubly clamped beam is anchored orattached.

[0014] An appropriately configured pivotless compliant microstructuremay be incorporated into the coupling assembly microstructure in thecase of the first aspect to at least assist in the provision of theforce redirection function (the “first condition”). A pivotlesscompliant microstructure, as used herein, means a microstructurehaving: 1) a plurality of flexible beams that are each attached oranchored (directly or indirectly) to the substrate at a discretelocation so as to be motionless relative to the substrate at theattachment or anchor location, and such that other portions of each suchflexible beam are able to move relative to the substrate by a flexing orbending-like action; 2) a plurality of cross beams that are not attachedto the substrate (other than through an interconnection with one or moreflexible beams), and that either interconnect a pair of flexible beamsat a location that is able to move relative to the substrate or thatinterconnect with one or more other cross beams; 3) an appropriate inputstructure (e.g., a single beam; a yoke) and an appropriate outputstructure (e.g., a single beam; a yoke); and 4) of a configuration thatexploits elastic deformation to achieve a desired movement of the inputstructure and the output structure relative to the substrate. Statedanother way, all movement the pivotless compliant microstructure isthrough a flexing of the same at/about one or more locations where thestructure is anchored to the substrate. This pivotless compliantmicrostructure may be configured to achieve any type/amount of motion ofits input structure relative to its output structure. For instance, theinput and output structures may move the same or different amounts inthe lateral dimension (at least generally parallel with the plane of thesubstrate). In the case where the output structure of the pivotlesscompliant microstructure moves more than its input structure, thepivotless compliant microstructure may be referred to as a displacementmultiplier. Therefore, a displacement multiplier is one type ofpivotless compliant microstructure which may be utilized in relation tothe first aspect.

[0015] Further features may be incorporated into the above-notedpivotless compliant microstructure in the case of the first aspect toenhance the manner in which a force from the second load microstructureis transmitted to the first load microstructure so as to be collinearwith the direction in which the first load microstructure moves relativeto the substrate (the “first condition”), to reduce the potential forcontact with the underlying substrate (the “second condition”), or acombination thereof. For instance, the pivotless compliantmicrostructure may utilize a relief structure as its output structureand that is attached to an elongate tether, that in turn is attached tothe second load microstructure (directly indirectly). This reliefstructure may be configured to reduce the amount that other portions ofthe pivotless compliant microstructure deflect toward the underlyingsubstrate when non-collinear forces are exerted on the relief structureand the input structure. Both the bending stiffness of this reliefstructure, how/where the relief structure is attached to the remainderof the pivotless compliant microstructure, or both may be selected suchthat the torque that is exerted on the remainder of the pivotlesscompliant microstructure by the second load microstructure reduces thepotential for deflecting any portion of the pivotless compliantmicrostructure toward the substrate in an amount so as to contact anunderlying structure during normal operation of themicroelectromechanical system of the first aspect.

[0016] Other options may be utilized to address reducing the potentialfor undesired contact between portions of the microelectromechanicalsystem of the first aspect when using a pivotless compliantmicrostructure as at least part of the coupling assembly microstructure.For instance, the pivotless compliant microstructure may be allowed tomove at least generally away from the substrate so as to increase thespacing from the underlying structure. The pivotless compliantmicrostructure may be mounted on a frame (typically at four anchorlocations, although any appropriate number of anchor locations may beutilized), that in turn is pivotally interconnected with the substrateor that is interconnected with the substrate so as to allow at leastpart of the frame to be able to move at least generally away from thesubstrate. This frame may be configured as a one-piece structure or by aplurality of individual frame segments that are each interconnected withthe substrate in the above-noted manner and that collectively define theframe. Moreover, this frame may be configured so as to be rigid or so asto not flex to a significant degree, or at least may be configured so asto be more rigid than the pivotless compliant structure that is mountedthereon. In this case the pivotless compliant structure would move atleast generally away from the substrate (or further from the substrate)when exposed to non-collinear forces at its input and output structuresby a pivoting of the “free end” of the frame at least generally awayfrom the substrate. Another option is for the frame to be defined by onone or more pre-stressed elevators. A “pre-stressed elevator” is astructure that may be made by surface micromachining, and that whenreleased (after being exposed to one or more release etchants to removea sacrificial material used in the fabrication of themicroelectromechanical system of the first aspect, and likely furtherafter having one or more retention pins, fuses, or the like blown orruptured (a retention pin, fuse, or the like being used to retain theprestressed elevators in a predetermined position relative to thesubstrate until operation of the microelectromechanical system isinitiated)) has at least a portion thereof change its position relativeto the substrate. For instance, such a pre-stressed elevator may beanchored to the substrate during fabrication such that when released inthe above-noted manner, at least one end of the pre-stressed elevatormoves at least generally away from the substrate as a result of theenergy stored therein during fabrication. Stated another way, apre-stressed elevator may have a bent or curled configuration in thestatic state. Mounting the pivotless compliant microstructure on aportion of one or more of these pre-stressed elevators thereby increasesthe spacing between the pivotless compliant microstructure and thesubstrate, even prior to exposing its input and output structures tonon-collinear forces. Yet another option is to pivotally interconnectthe pivotless compliant microstructure itself with the substrate so asto allow part of the pivotless compliant microstructure to move at leastgenerally away from the substrate when exposed to non-collinear forces.In one embodiment, this pivotal interconnection of the pivotlesscompliant microstructure is provided by limiting the anchor locations ofthe pivotless compliant microstructure to the substrate to being atleast generally disposed along a common reference axis.

[0017] Another option for reducing the potential for contact as a resultof non-collinear forces being exerted on the input and output structureof a pivotless compliant microstructure is by forming a cavity under atleast a portion of the pivotless compliant microstructure (or statedanother way to increase the distance between at least a certain portionof the pivotless compliant microstructure and the underlying structurein the microelectromechanical system of the first aspect). Discretecavities may be formed in the substrate under those portions of thepivotless compliant microstructure that are susceptible to beingdeflected the furthest in the direction of the substrate when exposed tonon-collinear forces. In this case, the spacing between those portionsof the pivotless compliant microstructure that are susceptible to themost deflection could be spaced further from the underlying substratethan other portions of the pivotless compliant microstructure in thestatic state. Yet another option is to dispose the entire pivotlesscompliant microstructure in a cavity that is formed in the substrate. Arelated option would be to dispose at least a substantial portion of thepivotless compliant microstructure and its anchors to the substratewithin a single cavity that is formed in the substrate. For instance, asingle cavity could be formed in the substrate and all free ends ornodes of the pivotless compliant microstructure could be disposed inthis single cavity. “Free ends” or “nodes” in this sense are thoseportions of the pivotless compliant microstructure that in effect arethe extreme end of a cantilever or the like. Although the anchorsbetween the pivotless compliant microstructure and the substrate may bedisposed within a single cavity, in one embodiment all of the anchorsbetween the pivotless compliant microstructure and the substrate aredisposed outside of this cavity, while the remainder of the pivotlesscompliant microstructure is disposed within this single cavity.

[0018] Controlling the spacing between at least certain portions of thepivotless compliant microstructure and the underlying substrate may beused to address the second condition in relation to the first aspect asnoted. In one embodiment, at least a portion of the pivotless compliantmicrostructure and the underlying substrate are separated by a space ofat least about 7 microns. More preferably, each of the above-noted “freeends” or “nodes” of the pivotless compliant microstructure are separatedfrom the underlying substrate by the above-noted spacing. One way inwhich this may be achieved for the microelectromechanical system of thefirst aspect when fabricated by surface micromachining techniques is toform the various beams of the pivotless compliant microstructure fromonly two of the structural layer levels in this system.

[0019] Selecting the locations where the pivotless compliantmicrostructure is anchored to the substrate may also address thepotential for undesired contact between different portions of themicroelectromechanical system of the first aspect due to the existenceof non-collinear forces being exerted on the coupling assemblymicrostructure. The pivotless compliant microstructure may becharacterized as having a longitudinal extent progressing from its inputstructure to its output structure along a central, longitudinalreference axis. A pair of “lateral” extremes of the pivotless compliantmicrostructure are disposed on opposite sides of this central,longitudinal reference axis and correspond with those portions of thepivotless compliant microstructure that are disposed furthest from thiscentral, longitudinal reference axis. All anchor locations of thepivotless compliant microstructure to the substrate may be disposed atleast as far from the output structure of the pivotless compliantmicrostructure (measured along the central, longitudinal reference axisor a parallel axis) as these lateral extremes to address the secondcondition of the first aspect. Stated another way, all anchor locationsof the pivotless compliant microstructure to the substrate are disposedno farther from the input structure of the pivotless compliantmicrostructure than the noted lateral extremes, again measured along thecentral, longitudinal reference axis or a parallel axis.

[0020] A second aspect of the present invention is embodied in amicroelectromechanical system that includes a substrate that isappropriate for microelectromechanical fabrication, first and secondload microstructures, a force isolator microstructure, and first andsecond coupling microstructures. The first load microstructure isinterconnected with the substrate in any appropriate manner so as to beable to move relative to the substrate along a first path and in adirection that is typically at least generally parallel with a lateralextent of the substrate. The second load microstructure is alsointerconnected with the substrate in any appropriate manner so as to beable to move in at least some fashion relative to the substrate. Thefirst coupling microstructure extends between and interconnects thefirst load microstructure and the force isolator microstructure, whilethe second coupling microstructure extends between and interconnects thesecond load microstructure and the force isolator microstructure. Thefirst coupling microstructure allows a first force to be transmittedbetween the force isolator microstructure and the first loadmicrostructure. This first force is in a direction that is at leastgenerally collinear with the motion of the first load microstructurealong the first path. The second coupling microstructure allows a secondforce to be transmitted between the force isolator microstructure andthe second load microstructure. The first and second forces are notcollinear, and a resultant force that is exerted on the force isolatormicrostructure may be characterized as a third force. The exertion ofthis third force on the force isolator microstructure does not cause anyportion of the force isolator microstructure to be deflected intocontact with any underlying portion of the microelectromechanicalsystem.

[0021] Various refinements exist of the features noted in relation tothe subject second aspect of the present invention. Further features mayalso be incorporated in the subject second aspect of the presentinvention as well. These refinements and additional features may existindividually or in any combination. Each of the various features thatwere discussed above in relation to the first aspect may be used by thesecond aspect as well, alone or in any combination. Generally, the firstcoupling microstructure, the force isolator microstructure, and thesecond coupling microstructure of the second aspect would thencorrespond with the coupling assembly microstructure of the firstaspect. The force isolator microstructure of the second aspect could bethe pivotless compliant microstructure, the spacing between at least aportion of the pivotless compliant microstructure and the substrate, howthe pivotless compliant microstructure is interconnected with thesubstrate, how the second coupling assembly microstructure interconnectswith the pivotless compliant microstructure, the use of one or moredoubly clamped beams that are attached to the first coupling assemblymicrostructure and that are anchored to the substrate on opposite sidesthereof, or any combination thereof, all as discussed above in relationto the first aspect.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0022]FIG. 1A is a plan view of one embodiment of amicroelectromechanical system that includes a positioning assembly.

[0023]FIG. 1B is a plan view of a microelectromechanical optical systemthat utilizes a pair of the positioning assemblies illustrated in FIG.1A.

[0024]FIG. 1C is a schematic, side view of one embodiment of amicroelectromechanical system having a pair of load microstructures anda coupling assembly microstructure that compensates for non-collinearforces being exerted on the coupling assembly microstructure.

[0025]FIG. 1D is a schematic of representative forces that may beexerted on a force isolator microstructure of the coupling assemblymicrostructure of FIG. 1C.

[0026]FIG. 1E is a schematic, side view of one embodiment of amicroelectromechanical system having a pair of load microstructures anda coupling assembly microstructure that compensates for non-collinearforces being exerted on the coupling assembly microstructure.

[0027]FIG. 1F is a top view of the microelectromechanical system of FIG.1E.

[0028]FIG. 1G is a top view of a variation of the microelectromechanicalsystem of FIG. 1E.

[0029]FIG. 2 is a plan view of one embodiment of a relief structure on adisplacement multiplier that addresses downward deflection of thedisplacement multiplier when exposed to non-collinear forces.

[0030]FIG. 3 is a perspective view of another embodiment of a reliefstructure on a displacement multiplier that addresses downwarddeflection of the displacement multiplier when exposed to non-collinearforces.

[0031]FIG. 4 is a perspective view of another embodiment of a reliefstructure on a displacement multiplier that addresses downwarddeflection of the displacement multiplier when exposed to non-collinearforces.

[0032]FIG. 5 is a perspective view of another embodiment of a reliefstructure on a displacement multiplier that addresses downwarddeflection of the displacement multiplier when exposed to non-collinearforces.

[0033]FIG. 6 is a perspective view of another embodiment of a reliefstructure on a displacement multiplier that addresses downwarddeflection of the displacement multiplier when exposed to non-collinearforces.

[0034]FIG. 7 is a perspective view of another embodiment of a reliefstructure on a displacement multiplier that addresses downwarddeflection of the displacement multiplier when exposed to non-collinearforces.

[0035]FIG. 8 is a plan view of one embodiment of a displacementmultiplier that is mounted on a rigid frame, that in turn is pivotallyinterconnected with a substrate.

[0036]FIG. 9A is a plan view of one embodiment of a displacementmultiplier that is mounted on one embodiment of a frame assembly, thatin turn is pivotally interconnected with a substrate.

[0037]FIG. 9B is a plan view of one embodiment of a displacementmultiplier that is mounted on one embodiment of a frame assembly, thatin turn is pivotally interconnected with a substrate, and that also usesdoubly clamped beams.

[0038]FIG. 9C is a side view of one embodiment of a pre-stressed memberthat may be utilized by the frame/frame assembly of FIGS. 8-9B at a timeprior to executing an etch release.

[0039]FIG. 9D is a top view of the pre-stressed member of FIG. 9C afterbeing released.

[0040]FIG. 9E is a side view of the pre-stressed member of FIG. 9D.

[0041] FIGS. 10A-B are plan views of one embodiment of a displacementmultiplier that is pivotally interconnected with a substrate.

[0042]FIG. 11 is a plan view of one embodiment of a displacementmultiplier that is pivotally interconnected with a substrate, and thatutilizes a plurality of doubly clamped beams that are attached to aninput beam of the displacement multiplier.

[0043]FIG. 12A is a plan view of one embodiment of a positioningassembly that utilizes a doubly clamped beam that is attached to aninterconnecting elongate tether between an actuator output yoke and anelevator.

[0044]FIG. 12B is a plan view of another embodiment of a positioningassembly that utilizes a doubly clamped beam that is attached to aninterconnecting elongate tether between an actuator output yoke and anelevator.

[0045]FIG. 13 is a plan view of one embodiment of a displacementmultiplier, where a pair of cavities are formed in the substrate underthe “lateral extremes” of the displacement multiplier.

[0046]FIG. 14 is a plan view of one embodiment of a displacementmultiplier where its anchor locations for fixing the same to a substrateare selected to reduce the amount of deflection toward the substratewhen the displacement multiplier is exposed to non-collinear forces.

[0047]FIG. 15A is a plan view of one embodiment of a displacementmultiplier that is at least substantially disposed within a cavityformed in a substrate.

[0048]FIG. 15B is a perspective view of the embodiment of FIG. 15A.

[0049]FIG. 16A is a cross-sectional view at the wall of the cavity ofthe embodiment of FIGS. 15A-B.

[0050] FIGS. 16B-D are cross-sectional views of alternative embodimentsof wall configurations for the cavity of FIGS. 15A-B.

DETAILED DESCRIPTION OF THE INVENTION

[0051] The present invention will now be described in relation to theaccompanying drawings which at least assist in illustrating its variouspertinent features. The various embodiments to be described herein, andthe subject matter presented in the accompanying claims, are limited tomicroelectromechanical systems. One or more micro-devices ormicrostructures may define any given microelectromechanical system. Inany case, a substrate is used in the fabrication of each type ofmicroelectromechanical system contemplated by the inventors. The term“substrate” as used herein means those types of structures that can behandled by the types of equipment and processes that are used tofabricate micro-devices or microstructures on, within, and/or from asubstrate using one or more micro-photolithographic patterns. Althoughsurface micromachining is the preferred type of technique forfabricating the microelectromechanical systems described herein, othertechniques may be utilized as well. Moreover, in certain instances itmay be desirable to use a combination of two or more fabricationtechniques to define a given microelectromechanical system.

[0052] Since surface micromachining is the preferred fabricationtechnique for the microelectromechanical systems described herein, thebasis principles of surface micromachining will first be described.Initially, various surface micromachined microstructures and surfacemicromachining techniques are disclosed in U.S. Pat. Nos. 5,783,340,issued Jul. 21, 1998, and entitled “METHOD FOR PHOTOLITHOGRAPHICDEFINITION OF RECESSED FEATURES ON A SEMICONDUCTOR WAFER UTILIZINGAUTO-FOCUSING ALIGNMENT”; 5,798,283, issued Aug. 25, 1998, and entitled“METHOD FOR INTEGRATING MICROELECTROMECHANICAL DEVICES WITH ELECTRONICCIRCUITRY; 5,804,084, issued Sep. 8, 1998, and entitled “USE OF CHEMICALMECHANICAL POLISHING IN MICROMACHNNG”; 5,867,302, issued Feb. 2, 1999,and entitled “BISTABLE MICROELECTROMECHANICAL ACTUATOR”; and 6,082,208,issued Jul. 4, 2000, and entitled “METHOD FOR FABRICATING FIVE-LEVELMICROELECTROMECHANICAL STRUCTURES AND MICROELECTROMECHANICALTRANSMISSION FORMED, the entire disclosures of which are incorporated byreference in their entirety herein.

[0053] Surface micromachining generally entails depositing typicallyalternate layers of structural material and sacrificial material usingan appropriate substrate which functions as the foundation for theresulting microstructures. A dielectric isolation layer will typicallybe formed directly on an upper surface of the substrate on which such amicroelectromechanical system is to be fabricated, and a structurallayer will be formed directly on an upper surface of the dielectricisolation layer. This particular structural layer is typically patternedand utilized for establishing various electrical interconnections forthe microelectromechanical system which is thereafter fabricatedthereon. Other layers of sacrificial and structural materials are thensequentially deposited to define the various microstructures of themicroelectromechanical system. Various patterning operations (again,collecting masking, etching, and mask removal operations) may beexecuted on one or more of these layers before the next layer isdeposited so as to define the desired microstructure. After the variousmicrostructures have been defined in this general manner, the desiredportions of the various sacrificial layers are removed by exposing the“stack” to one or more etchants. This is commonly called “releasing” atleast certain of the microstructures from the substrate, typically toallow at least some degree of relative movement between themicrostructure(s) and the substrate. In certain situations, not all ofthe sacrificial material used in the fabrication is removed during therelease. For instance, sacrificial material may be encased within astructural material to define a microstructure with desiredcharacteristics (e.g., a prestressed elevator microstructure).

[0054] Exemplary materials for the above-noted sacrificial layersinclude undoped silicon dioxide or silicon oxide, and doped silicondioxide or silicon oxide (“doped” indicating that additional elementalmaterials are added to the film during or after deposition). Exemplarymaterials for the structural layers include doped or undoped polysiliconand doped or undoped silicon. Exemplary materials for the substrateinclude silicon. The various layers described herein may beformed/deposited by techniques such as chemical vapor deposition (CVD)and including low-pressure CVD (LPCVD), atmospheric-pressure CVD(APCVD), and plasma-enhanced CVD (PECVD), thermal oxidation processes,and physical vapor deposition (PVD) and including evaporative PVD andsputtering PVD, as examples.

[0055] Surface micromachining can be done with any suitable system of asubstrate, sacrificial film(s) or layer(s), and structural film(s) orlayer(s). Many substrate materials may be used in surface micromachiningoperations, although the tendency is to use silicon wafers because oftheir ubiquitous presence and availability. The substrate again isessentially a foundation on which the microstructures are fabricated.This foundation material must be stable to the processes that are beingused to define the microstructure(s) and cannot adversely affect theprocessing of the sacrificial/structural films that are being used todefine the microstructure(s). With regard to the sacrificial andstructural films, the primary differentiating factor is a selectivitydifference between the sacrificial and structural films to thedesired/required release etchant(s). This selectivity ratio ispreferably several hundred to one or much greater, with an infiniteselectivity ratio being preferred. Examples of such a sacrificialfilm/structural film system include: various silicon oxides/variousforms of silicon; poly germanium/poly germanium-silicon; variouspolymeric films/various metal films (e.g., photoresist/aluminum);various metals/various metals (e.g., aluminum/nickel);polysilicon/silicon carbide; silicon dioxide/polysilicon (i.e., using adifferent release etchant like potassium hydroxide, for example).Examples of release etchants for silicon dioxide and silicon oxidesacrificial materials are typically hydrofluoric (HF) acid based (e.g.,undiluted or concentrated HF acid, which is actually 49 wt % HF acid and51 wt % water; concentrated HF acid with water; buffered HF acid (HFacid and ammonium fluoride)).

[0056] Only those portions of a microelectromechanical system that arerelevant to the present invention will be described in relation to thefollowing embodiments. The entirety of these various embodiments ofmicroelectromechanical systems are defined by a plurality ofmicrostructures, including structures that span feature sizes of lessthan 1 micron to many hundreds of microns. For convenience, the word“microstructure” may not be repeated in each instance in relation toeach of these components. However, each such component is in fact amicrostructure and “microstructure” is a structural limitation in theaccompanying claims. Since the same (structurally and/or functionally)microstructure may be used in a variety of these embodiments, a briefdiscussion of the least some of these microstructures will be providedin an attempt to minimize repetitious description.

[0057] One or more microstructures of the various embodiments ofmicroelectromechanical systems to be described herein move relative toother portions of the microelectromechanical system, and including asubstrate that is used in the fabrication of the microelectromechanicalsystem. Unless otherwise noted as being a key requirement for aparticular embodiment, this relative movement may be achieved in anyappropriate manner. Surface micromachining fabrication techniques allowfor relative movement without having any rubbing or sliding contactbetween a movable microstructure and another microstructure or thesubstrate. All movement of a surface micromachined microstructurerelative to the substrate is provided by a flexing or elasticdeformation of one or more microstructures of the microelectromechanicalsystem. Another option that may be utilized to allow a givenmicrostructure to move relative to the substrate is to interconnect twoor more microstructures together in a manner such that there is relativemovement between these microstructures while the microstructures are ininterfacing relation at least at some point in time during the relativemovement (e.g., a hinge connection; a ball and socket connection).

[0058] At least one actuator may be utilized by the various embodimentsof microelectromechanical systems to be described herein. Unlessotherwise noted as being a key requirement for a particular embodiment,each of the following actuator characteristics or attributes will beapplicable. Any appropriate type of actuator may be utilized.Appropriate types of actuators include without limitation electrostaticcomb actuators, thermal actuators, piezoelectric actuators, magneticactuators, and electromagnetic actuators. Moreover, any appropriate wayof interconnecting an actuator with the substrate may be utilized. Oneactuator may be utilized to exert the desired force on a givenmicrostructure, or multiple actuators may be interconnected in a mannerto collectively exert the desired force on a given microstructure. Themovement of an actuator may be active (via a control signal or a changein a control signal), passive (by a stored spring force or the like), ora combination thereof.

[0059] One or more of the various embodiments of microelectromechanicalsystems to be described herein utilize what may be characterized as anelongate coupling or tether to interconnect two or more microstructures.Unless otherwise noted as being a key requirement for a particularembodiment, any appropriate configuration may be used for any suchtether. In at least certain applications, it may be desirable to havethis tether be “stiff.” Cases where a tether of this configuration isdesired or preferred will be referred to as a “stiff tether.” A “stifftether” means that such a tether is sufficiently stiff so as to notbuckle, flex, or bow to any significant degree when exposed to externalforces typically encountered during normal operation of themicroelectromechanical system. As such, no significant elastic energy isstored in the tether, the release of which could adversely affect one ormore aspects of the operation of the microelectromechanical system.

[0060] One or more of the various embodiments of microelectromechanicalsystems to be described herein may use an elevator or the like. Thiselevator is interconnected with the substrate in a manner such that atleast part of the elevator is able to move at least generally away fromor toward the substrate. Whether at least part of the elevator moves atleast generally away from or at least generally toward the substrate isdependent upon the direction of the resulting force that is acting onthe elevator. Unless otherwise noted as being a key requirement for aparticular embodiment, each of the following elevator characteristicswill be applicable. Any way of interconnecting the elevator with thesubstrate that allows for the desired relative movement between theelevator and the substrate may be utilized. Any configuration may beused for the elevator that allows for the desired relative movementbetween the elevator and the substrate may be utilized (single ormultiple beam structures of any appropriate configuration). The desiredmovement of the elevator relative to the substrate may be along any path(e.g., along an arcuate path) and in any orientation relative to thesubstrate (e.g., along a path that is normal to the substrate; along apath that is at an angle other than 90° relative to the substrate).

[0061] One or more of the various embodiments of microelectromechanicalsystems to be described herein may use what is characterized as adisplacement multiplier. A displacement multiplier is one type ofpivotless compliant structure as noted above. Unless otherwise noted asbeing a key requirement for a particular embodiment, each of thefollowing characteristics for a displacement multiplier will beapplicable. Any layout of interconnected beams may be used to define thedisplacement multiplier, each of these beams may be of any appropriateconfiguration, and the displacement multiplier may be anchored to thesubstrate using any appropriate number of anchor locations and anchorlocation positionings. The input and output structures of thedisplacement multiplier may be of any appropriate configuration, andfurther may be disposed in any appropriate orientation relative to eachother. The displacement multiplier may be configured to achieve anytype/amount of motion of its input structure relative to its outputstructure. For instance, the input and output structures of thedisplacement multiplier may move the same or different amounts in thelateral dimension, and along any appropriate path. Although thedisplacement multiplier may be symmetrically disposed relative to areference axis, such need not be the case.

[0062] One or more of the various embodiments of microelectromechanicalsystems to be described herein may use one or more doubly clamped beams.The basic function of such a doubly clamped beam is to compensate forthe existence of non-collinear forces. This may be subject to a numberof characterizations. One way to characterize this compensation is thatsuch a doubly clamped beam redirects a force. Another way tocharacterize this compensation is that such a doubly clamped beamreduces the magnitude of a vertical force component that is transmittedto a microstructure to which the doubly clamped beam is anchored orattached. Any such doubly clamped beam includes a beam that is attachedto another microstructure (e.g., to a tether), and further that isanchored to the substrate on both sides of this microstructure. In thecase of a surface micromachined system, a given doubly clamped beam maybe formed in the same structural layer as the microstructure to whichthe doubly clamped beam is attached (e.g., disposed the same distancefrom the substrate). The fixation or attachment of any such doublyclamped beam to such a microstructure in this case would be via anintegral construction. That is, there would be no evident mechanicaljoint between the doubly clamped beam and the microstructure to which itis attached in this case. Each doubly clamped beam also may be formedfrom multiple, vertically spaced structural layers in a surfacemicromachined configuration, where these multiple structural layers areappropriately anchored to each other. However, the doubly clamped beamwould still be somehow attached to the microstructure.

[0063] One embodiment of a positioning assembly 4 for amicroelectromechanical system is illustrated in FIG. 1A. The positioningassembly 4 includes an actuator 64. Typically the actuator 64 will movein two different directions to either move the elevator 20 at leastgenerally away from the substrate 8 or to move the elevator 20 at leastgenerally toward the substrate 8. The actuator 64 is of theelectrostatic type and includes several stationary electrodes 68 a-dthat are fixed to the substrate 8 and several moveable electrodes 72 a-dthat are attached to a moveable frame or output bar 80. The output bar80 is supported above the substrate 8 by a folded support springassembly 76 that is anchored to the substrate 8 at four anchor points 82to permit lateral movement of the output bar 80 relative to thesubstrate 8. “Lateral” or the like as used herein means at leastgenerally parallel with an upper surface or the general extent of thesubstrate 8 (for instance, “horizontal”). Upon application of a controlvoltage via electrical interconnects (not shown) across the electrodes68 a-d, 72 a-d, the moveable electrodes 72 a-d are pulled laterallytowards the stationary electrodes 68 a-d, thereby moving the output bar80 laterally in one direction. The amount of lateral movementcorresponds with the magnitude of the actuation voltage applied. Whenthere is a change in the actuation voltage, the actuator 64 moves in theopposite direction utilizing at least the spring force that wasoriginally stored in the support spring assembly 76 (i.e., forces fromone or more other sources may contribute to this movement of theactuator 64).

[0064] The output bar 80 of the actuator 64 is appropriately coupled toa displacement multiplier 44. The displacement multiplier 44 includes aplurality of interconnected beams 48 a-l and is interconnected with thesubstrate 8 at four anchors locations 50 a-d so as to pivot about theseanchor locations 50 a-d by a flexure of various of the beams 48(typically those beams 48 that are directly attached to an anchor 50).An input structure or first coupling 60 of the displacement multiplier44 is appropriately interconnected with the actuator 64 (morespecifically the output bar 80), while an output structure or secondcoupling 52 of the displacement multiplier 44 is appropriatelyinterconnected with an elongate tether or coupling 40. The firstcoupling 60 and the second coupling 52 of the displacement multiplier 44are longitudinally spaced relative to a central, longitudinal referenceaxis 99 along which the displacement multiplier 44 at least generallyextends. Moreover, the first coupling 60 and the second coupling 52 aredisposed along this axis 99 as well.

[0065] Lateral movement of the movable electrodes 72 a-d of the actuator64 exerts an input force on the displacement multiplier 44 at the firstcoupling 60 to cause at least a lateral movement thereof (and which mayalso cause the first coupling 60 to flex as well), which in turn causesthe various beams 48 of the displacement multiplier 44 to pivot relativeto the substrate 8 about the four anchor locations 50 at least generallywithin the lateral dimension and/or relative to other beams 48, which inturn moves the second coupling 52 of the displacement multiplier 44 inthe lateral dimension. In the illustrated embodiment, the amount oflateral movement of the second coupling 52 of the displacementmultiplier 44 is greater than the amount of lateral movement of thefirst coupling 60 of the displacement multiplier 44 (e.g.,amplification) for any given amount of lateral movement of the actuator64.

[0066] The elevator 20 has a base 21 that is movably interconnected withthe substrate 8, as well as a free end or apex 22 that is movable atleast generally away from and towards the substrate 8. The elevator 20is in the form of an A-frame in the illustrated embodiment and iseffectively a lever arm of sorts. More specifically, the elevator 20 isdefined by a pair of elevation members 24 a-b. One end of each elevationmember 24 is interconnected with the substrate 8 by an anchor 28 and aninterconnect 32 that is more a pliable or flexible (or stated anotherway, less rigid) than its corresponding elevation member 24. Theinterconnects 32 may then be characterized as a compliant member,flexure, or the like. The “pivotally” connected end of the elevator 20is the base 21. The opposite end of the elevator 20, namely the apex 22,is free to move at least generally away from/toward the substrate 8.That is, the apex 22 of the elevator 20 is not directly attached to thesubstrate 8 and is thereby able to move at least generally awayfrom/toward the substrate 8 by a pivoting action at least generallyabout an axis that extends through the anchors 28 a-b at the base 21 ofthe elevator 20 to provide the desired positioning function for theassembly 4. In the illustrated embodiment, the tether 40 isinterconnected with a beam 36 that extends between and structurallyinterconnects the pair of elevation members 24. The beam 36 may bedisposed anywhere between the base 21 and the apex 22 of the elevator20. In fact, any way of interconnecting the tether 40 with the elevator20 may be utilized.

[0067] One embodiment of a microelectromechanical system 2 that utilizesthe above-described positioning assembly 4 is illustrated in FIG. 1B.The microelectromechanical system 2 includes a pair of positioningassemblies 4 for moving a mirror 12 at least generally away from/towardthe substrate 8. Any appropriate number of positioning assemblies 4 maybe utilized to achieve a desired movement of the mirror 12 relative tothe substrate 8 (including using only a single positioning assembly 4 ormultiple positioning assemblies 4), and any appropriate way ofinterconnecting the positioning assemblies 4 with the mirror 12 may beutilized as well so long as the point of interconnection is spaced fromthe base 21 of the elevator 20 (or stated another way such that thepoint of interconnection is at a location on the elevator 20 that isable to move at least generally away from/toward the substrate 8 duringa lateral movement of the corresponding actuator 64 so as to move themirror 12 at least generally away from/toward the substrate 8). In theillustrated embodiment, each elevator 20 is interconnected with themirror 12 by a mirror interconnect 16. Any appropriate way of moving themirror 12 relative to the substrate 8 may be utilized. In theillustrated embodiment, the mirror 12 is also pivotally connected withthe substrate 8 by a mirror interconnect 18 at an anchor location 19.Other ways of pivotally interconnecting the mirror 12 with the substrate8 could be utilized to achieve a different type of motion of the mirror12 relative to the substrate 8. Moreover, the entirety of theinterconnection of the mirror 12 with the substrate 8 may be providedthrough the positioning assembly(ies) 4.

[0068] Summarizing the operation of the microelectromechanical system 2,because each elevator 20 is anchored to the substrate 8 at its base 21,when the associated tether 40 is moved laterally by a lateral movementof the associated actuator 64 in one direction and a resultant lateralmovement of both the first and second couplings 60, 52 of the associateddisplacement multiplier 44, the apex 22 of the associated elevator 20 ispivoted at least generally away from the substrate 8 at least generallythrough an arc to apply an at least generally upwardly-directed force tothe mirror 12 at a location where the mirror 12 is attached to each suchelevator 20. In essence, the elevators 20 act as lever arms to lift themirror 12 (or at least a portion thereof) at least generally away fromthe substrate 8. Similarly, when the associated tether 40 is movedlaterally by a lateral movement of the associated actuator 64 in adifferent direction (e.g., opposite to the first noted instance) and aresultant lateral movement of both the first and second couplings 60, 52of the associated displacement multiplier 44, the apex 22 of theassociated elevator 20 is pivoted at least generally toward thesubstrate 8 to apply an at least generally downwardly-directed force tothe mirror 12 at a location where the mirror 12 is attached to theelevator 20. As such, increasing the length of the lever arms (elevators20) increases the amount of vertical displacement of the mirror 12relative to the substrate 8 for a given angular displacement of thelever arms. Since the mirror 12 is also pivotally interconnected withthe substrate 8 by the mirror interconnect 18 at the anchor location 19,the mirror 12 also pivots relative to the substrate 8 as a result of anyforce applied to the mirror 12 by the pivoting elevators 20. Differenttypes of relative movement between the mirror 12 and the substrate 8 maybe realized by how/where each elevator 20 is interconnected with themirror 12, how/where (including if at all) the mirror 12 isinterconnected with the substrate 8, or both. Different types ofmovement of the mirror 12 relative to the substrate 8 also may berealized by the types of control signals provided to each of theactuators 64 and/or the direction of movement of each of the actuators64. For instance equal or unequal control signals may be sent to thepair of actuators 64 associated with the pair of elevators 20 and willaffect how the mirror 12 moves relative to the substrate 8. Moreover,one elevator 20 may be moved at least generally away from the substrate8, while another elevator 20 may be moved at least generally toward thesubstrate 8.

[0069] The displacement multiplier 44 is exposed to non-collinear forcesby the pivoting of its corresponding elevator 20 relative to thesubstrate 8, which in turn is achieved by a lateral movement of theactuator 64 in the relevant direction. That is, the resultant force thatis exerted on the displacement multiplier 44 at its first coupling 52 isnot collinear with the resultant force that is exerted on thedisplacement multiplier 44 at its second coupling 60. Exposure of thedisplacement multiplier 44 to such non-collinear forces may adverselyaffect the operation of microelectromechanical system 2 in one or morerespects. For instance, such non-collinear forces may result in anundesired contact or rubbing between different components of themicroelectromechanical system 2 (e.g., between the displacementmultiplier 44 and an underlying structure, such as the substrate 8).Such non-collinear forces may also have an adverse effect on the motionof the corresponding actuator 64 (e.g., exposing the actuator 64 to abinding-like force). Finally, such non-collinear forces may adverselyaffect the ability to control one or more microstructures of themicroelectromechanical system 2 to the desired degree and/or in thedesired manner. Various general configurations of microelectromechanicalsystems that include/generate non-collinear forces will now bedescribed, followed by various ways in which the existence of suchnon-collinear forces may be addressed in a microelectromechanical systemso as to at least reduce the effects of these non-collinear forces onone or more aspects of the corresponding microelectromechanical system.

[0070]FIG. 1C illustrates one embodiment of a microelectromechanicalsystem 500 that is fabricated using an appropriate substrate 504 andthat compensates for the existence of non-collinear forces in a desiredmanner. The microelectromechanical system 500 includes a first loadmicrostructure 508 that is movably interconnected with the substrate 504in any appropriate manner by a connection 510 for movement along anyappropriate path P₁, in any appropriate manner (e.g., linear, arcuate),and in any appropriate orientation relative to the substrate 504. Asecond load microstructure 528 is disposed at a different elevation inthe microelectromechanical system 500 than the first load microstructure508 (e.g., the distance between the first load microstructure 508 andthe substrate 504 is different than the distance between the second loadmicrostructure 528 and the substrate 504). The second loadmicrostructure 528 is also movably interconnected with the substrate 504in any appropriate manner by a connection 530 for movement along anyappropriate path P₂, in any appropriate manner (e.g., linear, arcuate),and in any appropriate orientation relative to the substrate 504.Movement of the second load microstructure 528 may be in response to anactuated movement of the first load microstructure 508, or vice versa.Both the first load microstructure 508 and the second loadmicrostructure 528 could be actuated for movement relative to thesubstrate 504 as well. How/why the first load microstructure 508 and thesecond load microstructure 528 move relative to the substrate 504 is notof particular significance—only that the first load microstructure 508and second load microstructure 528 at least at some point in time movealong non-collinear paths so as to exert non-collinear forces on aninterconnecting structure therebetween.

[0071] Extending between and interconnecting the first loadmicrostructure 508 and the second load microstructure 528 is a couplingassembly microstructure 524 that is movably interconnected with thesubstrate 504 in any appropriate manner by a connection 518. Componentsof the coupling assembly microstructure 524 include a first couplingmicrostructure 512, a force isolator microstructure 516, and a secondcoupling microstructure 520. The first coupling microstructure 512extends between and interconnects the first load microstructure 508 andthe force isolator microstructure 516, while the second couplingmicrostructure 520 extends between and interconnects the force isolatormicrostructure 516 and the second load microstructure 528. It should beappreciated that the arrangement illustrated in FIG. 1C exertsnon-collinear forces on the force isolator microstructure 516,representative ones of which are illustrated in FIG. 1D. Movement of thefirst load microstructure 528 relative to the substrate 504 exerts aforce F₁ on the force isolator microstructure 516, while the second loadmicrostructure exerts a force F₂ on the force isolator microstructure516 that is non-collinear with the force F₁. The resultant force on thecoupling assembly microstructure 524 may correspond with a force that isdirectly opposite to the force F₃ illustrated in FIG. 1C. The force F₃is what may be characterized as a compensating force that is at leastgenerally directed toward the substrate 504 in the illustratedembodiment and that is in effect generated by the force isolatormicrostructure 516 so that the net force acting on the coupling assemblymicrostructure 524 is preferably zero. Stated another way, the couplingassembly microstructure 524 redirects the force F₂ such that the sameacts upon the first load microstructure 508 along a path that is atleast generally collinear with the path P₁. Moreover, themicroelectromechanical system 500 is configured such that no portion ofthe coupling assembly microstructure 524 is deflected into engagementwith any underlying structure, including the substrate 504, by theexistence of the non-collinear forces F₁ and F₂. That is, the resultantforce does not cause any contact or rubbing action between the couplingassembly microstructure 524 and any underlying portion of themicroelectromechanical system 500 and including the substrate 504.Representative ways in which one or both of these functions may berealized will be discussed in more detail below in relation to FIGS.2-16D.

[0072]FIG. 1E illustrates another embodiment of a microelectromechanicalsystem 532 that is fabricated using a substrate 536, and thatcompensates for the existence of non-collinear forces in a desiredmanner. The microelectromechanical system 532 includes a first loadmicrostructure 540 that is movably interconnected with the substrate 536in any appropriate manner by a connection 544 for movement along anyappropriate path P₁, in any appropriate manner (e.g., linear, arcuate),and in any appropriate orientation relative to the substrate 536. Asecond load microstructure 568 is disposed at the same elevation in themicroelectromechanical system 532 as the first load microstructure 568(e.g., the distance between the first load microstructure 540 and thesubstrate 536 is the same as the distance between the second loadmicrostructure 568 and the substrate 536). The second loadmicrostructure 568 is also movably interconnected with the substrate 536in any appropriate manner by a connection 572 for movement along anyappropriate path P₂, in any appropriate manner (e.g., linear, arcuate),and in any appropriate orientation relative to the substrate 536.Movement of the second load microstructure 568 may be in response to anactuated movement of the first load microstructure 540, or vice versa.Both the first load microstructure 540 and the second loadmicrostructure 568 could be actuated for movement relative to thesubstrate 536 as well. How/why the first load microstructure 540 and thesecond load microstructure 568 move relative to the substrate 536 is notof particular significance—only that the first load microstructure 540and second load microstructure 568 at least at some point in time movealong non-collinear paths so as to exert non-collinear forces on aninterconnecting structure therebetween.

[0073] Extending between and interconnecting the first loadmicrostructure 540 and the second load microstructure 568 is a couplingassembly microstructure 564 that is movably interconnected with thesubstrate 536 in any appropriate manner by a connection 556. Componentsof the coupling assembly microstructure 564 include a first couplingmicrostructure 548, a force isolator microstructure 552, and a secondcoupling microstructure 560. The first coupling microstructure 548extends between and interconnects the first load microstructure 540 andthe force isolator microstructure 552, while the second couplingmicrostructure 560 extends between and interconnects the force isolatormicrostructure 552 and the second load microstructure 568.

[0074] The first load microstructure 540 and the second loadmicrostructure 568 may be positioned in any manner on the substrate 536so as to exert non-collinear forces on the force isolator microstructure552. One such arrangement is illustrated in FIG. 1F, where the secondload microstructure 568 is parallel to but offset from the first loadmicrostructure 540 and the force isolator microstructure 552, and wherethe second load microstructure 568 moves along any appropriate path thatis not collinear with the path P₁ of the first load microstructure 540.Representative paths along which the second load microstructure 568 maymove in this manner are designated as P₂ and P₂ ^(i) in FIG. 1F. Anotherarrangement is illustrated in FIG. 1G, where the first loadmicrostructure 540, the force isolator microstructure 552, and thesecond load microstructure 568 are at least at some time axiallyaligned, but where the first microstructure 540 and the second loadmicrostructure 568 move along non-collinear paths relative to thesubstrate 536. Representative paths along which the second loadmicrostructure 568 may move in this manner are designated as paths P₂^(ii) and P₂ ^(iii) in FIG. 1G, while a representative path along whichthe first load microstructure 540 may move is designated as path P₁.

[0075] It should be appreciated that the arrangements illustrated inboth FIGS. 1F and 1G exert non-collinear forces on the force isolatormicrostructure 552, and which may expose the coupling assemblymicrostructure 564 to a resultant force that may be at least generallydirected toward the substrate 536. Generally, the coupling assemblymicrostructure 564 redirects the force exerted on the coupling assemblymicrostructure 564 by the second load microstructure 568, such that thesame acts upon the first load microstructure 540 along a path that is atleast generally collinear with its path P₁. Moreover, themicroelectromechanical system 532 is configured such that no portion ofthe coupling assembly microstructure 564 is deflected into engagementwith any underlying structure of the microelectromechanical system 532,and including substrate 536, by the existence of the non-collinearforces that are exerted on the coupling assembly microstructure 564 bythe first load microstructure 540 and the second load microstructure568. Representative ways in which both of these functions may berealized will be discussed in more detail below in relation to FIGS.2-16D.

[0076] There are two key aspects to compensating for the existence ofnon-collinear forces in a microelectromechanical system. One isincluding appropriate structure in the system to redirect a first forcethat is applied to/exerted on the microelectromechanical system so as tobe at least generally collinear with a second force that is appliedto/exerted on the microelectromechanical system. This force redirectionfunction may be provided at least in part by the displacement multiplier44 based upon the nature of a pivotless compliant microstructure.Consider the case of the FIG. 1A configuration where a first force F₁ isexerted on the first coupling 60, where a second force F₂ is exerted onthe second coupling 52, and where the direction or vector of the firstforce F₁ is not collinear with the direction or vector of the secondforce F₂. The displacement multiplier 44 may be configured to redirectthe second force F₂ so as to be at least generally collinear (therebyincluding being exactly collinear) with the first force F₁ at the firstcoupling 60, to redirect the first force F₁ so as to be at leastgenerally collinear with the second force F₂ at the second coupling 52,or both. Any configuration may be utilized for the displacementmultiplier 44 that provides this force redirection function in relationto at least one of multiple non-collinear forces.

[0077] Another key aspect to providing compensation for the existence ofnon-collinear forces in a microelectromechanical system is to configureat least part of the microelectromechanical system that is exposed tonon-collinear forces in such a manner that it does not deflect towardand contact with or rub against any underlying portion of themicroelectromechanical system, and including the substrate. Consideragain the configuration of the positioning assembly 4 that is presentedin FIG. 1A. Here the tether 40 is attached at one end to the outputstructure or second coupling 52 of the displacement multiplier 44. Theopposite end of the tether 40 is attached to the elevator 20. When theactuator 64 moves the input structure or first coupling 60 of thedisplacement multiplier 44 at least generally toward the elevator 20,the free end or apex 22 of the elevator 20 moves at least generally awayfrom the substrate 8. Since the second coupling 52 of the displacementmultiplier 44 is interconnected with a portion of the elevator 20 thatis able to move at least generally away from the substrate 8 under theseconditions, this movement of the elevator 20 exerts a vertical forcecomponent on the second coupling 52 of the displacement multiplier 44.Because the second coupling 52 has at some degree of stiffness, thisvertical force component results in a torque being applied to thedisplacement multiplier 44 at least generally about an axis that passesthrough what may be characterized as nodes 49 a and 49 b of thedisplacement multiplier 44. Node 49 a is at least generally that areawhere the beams 48 a and 48 c of the displacement multiplier 44intersect. Node 49 b is at least generally that area where the beams 48b and 48 d of the displacement multiplier 44 intersect.

[0078] In the configuration utilized by the displacement multiplier 44,lateral extremes or nodes 46 a and 46 b of the displacement multiplier44 would likely experience the largest amount of downwardly directedmotion (i.e., toward the substrate 8) as a result of the application ofthe above-noted torque on the displacement multiplier 44. The lateralextremes or nodes 46 a, 46 b are those portions of the displacementmultiplier 44 ^(i) that are disposed furthest from the central,longitudinal reference axis 99. In the event that the second coupling 52is of a sufficient stiffness, the nodes 46 a and/or 46 b will contactthe substrate 8 due to the above-noted torque. In this regard, when thesecond coupling 52 is fabricated by surface micromachining so as to havemultiple, vertically spaced layers that are anchored to each other at anappropriate number of locations, the second coupling 52 will likely besufficiently stiff that the noted contact will occur. Any such contactis not desirable for one or more applications that may utilize thepositioning assembly 4.

[0079] The embodiments of FIGS. 2-7 generally address the forces thatare exerted on the displacement multiplier by a movement of the apex 22of the elevator 20 relative to the substrate 8. Generally, each of theseembodiments provide an option for changing how a displacement multiplierdeforms when a force of the above-noted type is exerted thereon by thetether 40, such that no portion of the displacement multiplier deflectsinto contact with the underlying substrate. In the case of theembodiment of FIG. 3, the magnitude of the torque that is exerted on thedisplacement multiplier 44 ^(ii) as a result of the transmission of avertical force component to the displacement multiplier 44 ^(ii) by thetether 40 is reduced by having the tether 40 attach to a less rigidstructure of the displacement multiplier 44 ^(ii) than in the case ofthe displacement multiplier 44 of FIG. 1A. In the case of theembodiments of FIGS. 4-6, a counteracting or opposing torque is actuallygenerated that reduces the total torque that is exerted on thecorresponding displacement multiplier. In both scenarios, the reductionin the amount of torque that is exerted on a displacement multiplier bythe various configurations to be discussed in turn reduces the amountthat the displacement multiplier will deflect toward the underlyingsubstrate.

[0080]FIG. 2 illustrates one embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the amount of downward deflection of thedisplacement multiplier 44 when exposed to non-collinear forces. The“superscript” in relation to the displacement multiplier 44 ^(i) of FIG.2 indicates that there is at least one difference from the displacementmultiplier 44 of FIGS. 1A-B, principally in relation to how the tether40 interfaces with the displacement multiplier 44, versus how it wouldinterface with the displacement multiplier 44 ^(i). Correspondingcomponents of the displacement multiplier 44 ^(i) and the displacementmultiplier 44 are identified by common reference numerals.

[0081] The displacement multiplier 44 ^(i) of FIG. 2 includes a reliefstructure 88 that reduces the amount of deflection of the displacementmultiplier 44 ^(i) toward the underlying substrate 8 when thedisplacement multiplier 44 ^(i) is exposed to non-collinear forces(including when a force having a vertical force component is exerted onthe relief structure 88). This relief structure 88 provides forinterconnection of the tether 40 with the displacement multiplier 44^(i). The first coupling 60 again is interconnected with the actuator64. Movement of the actuator 64 exerts a force on the first coupling 60that is not collinear with the force that is exerted on the reliefstructure 88 by the elevator 20 through the tether 40 as a result of themovement of the actuator 64. Generally, the relief structure 88 may beof any configuration that connects a load with the displacementmultiplier 44 ^(i) in a way such that no portion of the displacementmultiplier 44 ^(i) deflects an amount so as to contact with or rubagainst the substrate 8 during normal operation of the correspondingmicroelectromechanical system, and that itself will not deflect intocontact with or rub against the substrate 8 during normal operation ofthe corresponding microelectromechanical system.

[0082] The relief structure 88 includes a distal end 96 a and a proximalend 96 b. The second coupling 52 is illustrated in FIG. 2 as including adistal end 98 a and a proximal end 98 b. The distal end 96 a of therelief structure 88 extends beyond the distal end 98 a of the secondcoupling 52. Similarly, the proximal end 96 b of the relief structure 88extends beyond the proximal end 98 b of the second coupling 52. Therelief structure 88 interconnects with the second coupling 52, theintersection of the beams 48 a, 48 c (node 49 a), and the intersectionof beams 48 b and 48 d (node 49 b) of the displacement multiplier 44^(i) at an intermediate location between its distal end 96 a andproximal end 96 b.

[0083] The relief structure 88 is disposed at a different elevation thanthe second coupling 52, or stated another way is disposed a differentdistance from the substrate 8 that is used to fabricate the displacementmultiplier 44 ^(i). In one embodiment, the relief structure 88 is formedfrom a single structural layer in a surface micromachined system, whilethe second coupling 52 and the beams 48 are vertically spaced fromrelief structure 88 in the direction of the substrate 8 (i.e., closer tothe substrate 8) and are formed from multiple, vertically-spacedstructural layers that are appropriately pinned or anchored to eachother (discussed in more detail below). The relief structure 88 also maybe characterized as being more flexible or pliable (i.e., less rigid)than the second coupling 52 about an axis that extends between the nodes49 a, 49 b or one that is parallel thereto.

[0084] The tether 40 or other appropriate coupling structure attaches tothe distal end 96 a of the relief structure 88 to interconnect thedisplacement multiplier 44 ^(i) with the elevator 20 or any otherappropriate load. The relief structure 88 includes structure on eachside of the central, longitudinal reference axis 99 of the displacementmultiplier 44 ^(i) (preferably symmetrically relative thereto), whereasthe tether 40 is disposed collinear with this axis 99. Because thelateral movement of the tether 40 (via the corresponding actuator 64 andthe displacement multiplier 44 ^(i)) in turn moves the apex 22 of theelevator 20 relative to the substrate 8, the force exerted on the firstcoupling 60 of the displacement multiplier 44 ^(i) by a movement of theactuator 64 is not collinear with a force that is exerted on the reliefstructure 88 by the tether 40. The force that is exerted on the reliefstructure 88 will have a vertical force component that is transmitted tothe relief structure 88 through the tether 40. This in turn exerts atorque on the displacement multiplier 44 ^(i) that is directed at leastgenerally about an axis that extends through the nodes 49 a and 49 b inaccordance with the foregoing.

[0085] Generally, the configuration of the relief structure 88 and howthe same is interconnected with the remainder of the displacementmultiplier 44 ^(i) reduces the magnitude of the torque that is exertedon the displacement multiplier 44 ^(i) at least generally about an axisthat extends through the nodes 49 a, 49 b as a result of the existenceof the above-noted vertical force component. As a result of the reliefstructure 88 reducing the magnitude of the torque that is exerted on thedisplacement multiplier 44 ^(i) at least generally about an axis thatextends through the nodes 49 a, 49 b, the potential for undesiredcontact between the displacement multiplier 44 ^(i) and the substrate 8is similarly reduced. Reducing the torque by utilizing the reliefstructure 88 reduces the amount of deflection of at least a portion ofthe displacement multiplier 44 ^(i) toward the substrate 8.

[0086]FIG. 3 illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the amount of downward deflection of thedisplacement multiplier 44 when exposed to non-collinear forces. The“superscript” in relation to the displacement multiplier 44 ^(ii) ofFIG. 3 indicates that there is at least one difference from thedisplacement multiplier 44 of FIGS. 1A-B, principally in relation to howthe tether 40 interfaces with the displacement multiplier 44, versus howit interfaces with the displacement multiplier 44 ^(ii). Correspondingcomponents of the displacement multiplier 44 ^(ii) and the displacementmultiplier 44 are identified by common reference numerals.

[0087] The displacement multiplier 44 ^(ii) of FIG. 3 includes a reliefstructure 116 that reduces the amount of deflection of the displacementmultiplier 44 ^(ii) toward the underlying substrate 8 when exposed tonon-collinear forces (for instance, when a force having a vertical forcecomponent is exerted on the relief structure 116). This relief structure116 provides for interconnection of the tether 40 with the displacementmultiplier 44 ^(ii). The first coupling 60 again is interconnected withthe actuator 64. The actuator 64 exerts a force on the first coupling 60that is not collinear with the force that exerted on the reliefstructure 116 by the elevator 20 through the tether 40 as a result ofthe movement of the actuator 64. Generally, the relief structure 116 maybe of any configuration that connects a load with the displacementmultiplier 44 ^(ii) in a way such that no portion of the displacementmultiplier 44 ^(ii) deflects an amount so as to contact with or rubagainst the substrate 8 during normal operation of the correspondingmicroelectromechanical system, and itself will not deflect into contactwith or rub against the substrate 8 during normal operation of thecorresponding microelectromechanical system.

[0088] The relief structure 116 includes a distal end 117 a and aproximal end 117 b. The second coupling 52 a includes a distal end 119 aand a proximal end 119 b. The distal end 117 a of the relief structure116 extends beyond the distal end 119 a of the second coupling 52 a,similar to the FIG. 2 embodiment. However, unlike the embodiment of FIG.2, the proximal end 117 b of the relief structure 116 terminates at thesame longitudinal position relative to the central, longitudinalreference axis 99 of the displacement multiplier 44 ^(ii) as theproximal end 119 b of the second coupling 52 a (also corresponding withthe longitudinal position of the nodes 49 a, 49 b).

[0089] The relief structure 116 is disposed at a higher elevation thanthe second coupling 52 a. In the illustrated embodiment, the reliefstructure 116 is formed from a single structural layer 104 (which isalso used to form the tether 40) by surface micromachining, while thesecond coupling 52 a is vertically spaced from the relief structure 116(in the direction of the substrate 8) and is formed from two verticallyspaced structural layers 108, 112 that are appropriately pinned oranchored to each other by surface micromachining. The various beams 48of the displacement multiplier 44 ^(ii) are formed from each of thesemultiple structural layers 104, 108, and 112 as well, and are anchoredor pinned to each other at multiple, appropriate locations. Theprinciples of non-collinear compensation presented by the FIG. 3embodiment are not limited to the number of structural layers disclosedtherein.

[0090] The relief structure 116 is interconnected with the tether 40 inthe illustrated embodiment of FIG. 3. The relief structure 116 isdisposed on each side of the central, longitudinal reference axis 99 ofthe displacement multiplier 44 ^(ii) (preferably symmetrically relativethereto), whereas the tether 40 is disposed collinear with this axis 44.Because the lateral movement of the tether 40 (via the actuator 64 andthe displacement multiplier 44 ^(ii)) in turn moves the apex 22 of theelevator 20 relative to the substrate 8, the force exerted on the firstcoupling 60 of the displacement multiplier 44 ^(ii) by a movement of theactuator 64 is not collinear with a force that is exerted on the reliefstructure 116 by the tether 40. That is, a vertical force component istransmitted to the relief structure 116 through the tether 40. This inturn exerts at least a vertical force component on nodes 49 a and 49 bof the displacement multiplier 44 ^(ii). This in turn exerts a torque onthe displacement multiplier 44 ^(ii) that is directed at least generallyabout an axis that extends through the nodes 49 a and 49 b in accordancewith the foregoing.

[0091] The configuration of the relief structure 116 and how the reliefstructure 116 is interconnected with the remainder of the displacementmultiplier 44 ^(ii) reduces the magnitude of the torque that is exertedon the displacement multiplier 44 ^(ii) at least generally about an axisthat extends through the nodes 49 a, 49 b as a result of the existenceof the above-noted vertical force component. Specifically, the reliefstructure 116 is of a stiffness such that the displacement multiplier 44^(ii) will not deflect into contact with the underlying substrate 8during normal operation of a microelectromechanical system that includesthe displacement multiplier 44 ^(ii). That is, as a result of reducingthe magnitude of the torque that is exerted on the displacementmultiplier 44 ^(ii) at least generally about an axis that extendsthrough the nodes 49 a, 49 b, the potential for undesired contactbetween the displacement multiplier 44 ^(ii) and the substrate 8 issimilarly reduced. Reducing the torque by utilizing the relief structure116 reduces the amount of deflection of at least a portion of thedisplacement multiplier 44 ^(ii) toward the substrate 8.

[0092]FIG. 4 illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the amount of downward deflection of thedisplacement multiplier 44 when exposed to non-collinear forces. The“superscript” in relation to the displacement multiplier 44 ^(iii) ofFIG. 4 indicates that there is at least one difference from thedisplacement multiplier 44 of FIGS. 1A-B, principally in relation to howthe tether 40 interfaces with the displacement multiplier 44, versus howit interfaces with the displacement multiplier 44 ^(iii). Correspondingcomponents of the displacement multiplier 44 ^(iii) and the displacementmultiplier 44 are identified by common reference numerals.

[0093] The displacement multiplier 44 ^(iii) of FIG. 4 includes a reliefstructure 122 that reduces the amount of deflection of the displacementmultiplier 44 ^(iii) toward the underlying substrate 8 when thedisplacement multiplier 44 ^(iii) is exposed to non-collinear forces(for instance, when a force having a vertical force component is exertedon the relief structure 122). This relief structure 122 provides forinterconnection of the tether 40 with the displacement multiplier 44^(iii). The first coupling 60 again is interconnected with the actuator64. Movement of the actuator exerts a force on the first coupling 60that is not collinear with the force that is exerted on the reliefstructure 122 by the elevator 20 through the tether 40 as a result ofthe movement of the actuator 64. Generally, the relief structure 122 maybe of any configuration that connects a load with the displacementmultiplier 44 ^(iii) in a way such that no portion of the displacementmultiplier 44 ^(iii) deflects an amount so as to contact with or rubagainst the substrate 8 during normal operation of the correspondingmicroelectromechanical system, and itself will not deflect into contactwith or rub against the substrate 8 during normal operation of thecorresponding microelectromechanical system.

[0094] The relief structure 122 includes a distal end 123 a and aproximal end 123 b. The second coupling 52 b includes a distal end 125 aand a proximal end 125 b. The distal end 123 a of the relief structure122 is disposed at the same position along the central, longitudinalreference axis 99 of the displacement multiplier 44 ^(iii) as the distalend 125 a of the second coupling 52 b. However, the proximal end 123 bof the relief structure 122 extends slightly beyond the proximal end 125b of the second coupling 52 b in the longitudinal direction. In oneembodiment, the proximal end 123 b of the relief structure 122 and theproximal end 125 b of the second coupling 52 b are separated by adistance of about 5 microns that is measured along the central,longitudinal reference axis 99 of the displacement multiplier 44 ^(iii).

[0095] The relief structure 122 is disposed at a higher elevation thanthe second coupling 52 b. In the illustrated embodiment, the reliefstructure 122 is formed from only the structural layer 104 (which isalso used to form the tether 40) by surface micromachining, while thesecond coupling 52 b is vertically spaced from the relief structure 122(in the direction of the substrate 8) and is formed from two verticallyspaced structural layers 108, 112 that are appropriately pinned oranchored to each other by surface micromachining. The various beams 48of the displacement multiplier 44 ^(iii) are formed from each of thesemultiple structural layers 104, 108, and 112 as well, and are anchoredor pinned to each other at multiple, appropriate locations. Theprinciples of non-collinear force compensation presented by the FIG. 4embodiment are not limited to the number of structural layers disclosedtherein.

[0096] The relief structure 122 is interconnected with the tether 40 inthe illustrated embodiment of FIG. 4. The relief structure 122 isdisposed on each side of the central, longitudinal reference axis 99 ofthe displacement multiplier 44 ^(iii) (preferably symmetrically relativethereto), whereas the tether 40 is disposed collinear with this axis 99.Because the lateral movement of the tether 40 (via the actuator(s) 64and the displacement multiplier 44 ^(iii)) in turn moves the apex 22 ofthe elevator 20 relative to the substrate 8, the force exerted on thefirst coupling 60 of the displacement multiplier 44 ^(ii) by a movementof the actuator 64 is not collinear with a force that is exerted on therelief structure 122 by the tether 40. That is, a vertical forcecomponent is transmitted to the relief structure 122 through the tether40. This in turn exerts a torque on the displacement multiplier 44 ^(ii)that is directed at least generally about an axis that extends throughthe nodes 49 a and 49 b in accordance with the foregoing.

[0097] Generally, the configuration of the relief structure 122 and howthe relief structure 122 is interconnected with the remainder of thedisplacement multiplier 44 ^(iii) reduces the magnitude of the torquethat is exerted on the displacement multiplier 44 ^(iii) at leastgenerally about an axis that extends through the nodes 49 a, 49 b as aresult of the existence of the above-noted vertical force component. Theapplication of a vertical force component on the distal end 123 a of therelief structure 122 produces both a torque and a force at the proximalend 123 b of the relief structure 122 because the relief structure 122does have some level of stiffness associated therewith. However, thevertical force component of the force acting at the proximal end 123 bresults in a torque of an opposite sign than that produced by theapplication of a vertical force component to the distal end 123 a of therelief structure 122. That is, the torque that results from theapplication of the vertical force component to the proximal end 123 bopposes the torque that results from the application of the verticalforce component at the distal end 123 a. As such, the net torque aboutan axis that extends between nodes 49 a and 49 b is desirably reduced.Changing the location of the proximal end 123 b relative to an axis thatextends through the nodes 49 a, 49 b will change the magnitude of thiscounteracting or opposing torque. There may be other ways to generate anopposing torque as well. In any case, as a result of reducing themagnitude of the net torque that is exerted on the displacementmultiplier 44 ^(iii) at least generally about an axis that extendsthrough the nodes 49 a, 49 b, the potential for undesired contactbetween the displacement multiplier 44 ^(iii) and the substrate 8 issimilarly reduced. That is, reducing the net torque by utilizing therelief structure 122 reduces the amount of deflection of at least aportion of the displacement multiplier 44 ^(iii) toward the substrate 8.

[0098]FIG. 5 illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the amount of downward deflection of thedisplacement multiplier 44 when exposed to non-collinear forces. Theconfiguration of FIG. 5 is similar to that of FIG. 4. The primarydifference is that the proximal end 123 ^(iv) of the relief structure122 ^(iv) and the proximal end 125 b of the second coupling 52 b areseparated by a greater distance in the FIG. 5 embodiment than in theFIG. 4 embodiment. In the FIG. 5 embodiment, the proximal end 123 b^(iv) of the relief structure 122 ^(iv) and the proximal end 125 b ofthe second coupling 52 b are separated by a distance of at least about10 microns measured along the central, longitudinal reference axis 99 ofthe displacement multiplier 44 ^(iv). Increasing the distance of theproximal end 123 b ^(iv) from an axis that extends through the nodes 49a, 49 b increases the magnitude of the opposing torque in accordancewith the foregoing.

[0099]FIG. 6 illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the amount of downward deflection of thedisplacement multiplier 44 when exposed to non-collinear forces. Theconfiguration of FIG. 6 is similar to the configurations of FIGS. 4-5.The primary difference is that the proximal end 123 b ^(v) of the reliefstructure 122 ^(v) and the proximal end 125 b of the second coupling 52b are separated by an even greater distance in the FIG. 6 embodimentthan in the FIG. 5 embodiment. In the FIG. 6 embodiment, the proximalend 123 b ^(v) of the relief structure 122 ^(v) and the proximal end 125b of the second coupling 52 b are separated by a distance of at leastabout 30 microns measured along the central, longitudinal reference axis99 of the displacement multiplier 44 ^(v). Increasing the distance ofthe proximal end 123 b ^(v) from an axis that extends through the nodes49 a, 49 b increases the magnitude of the opposing torque in accordancewith the foregoing.

[0100] The embodiments of FIGS. 2-6 are similar in that each utilizes arelief structure having a distal end that is interconnected with thetether 40 and that is interconnected with a remainder of thedisplacement multiplier such that a reduced net torque is exerted on thedisplacement multiplier. Various modifications of the configuration ofthe relief structure and/or the manner of interconnecting the same withthe remainder of the displacement multiplier in each of theseembodiments may have an effect not only on the magnitude of the torquethat is exerted on the corresponding displacement multiplier 44 about anaxis that extends through the nodes 49 a, 49 b, but on how these forcesare transmitted to this displacement multiplier 44 as well. Where therelief structure is anchored to the remainder of the displacementmultiplier 44, as well as the location of the proximal end of the reliefstructure relative to nodes 49 a, 49 b, are but a couple of the factorsthat may have an effect on how the displacement multiplier 44 respondsto the application of vertical force component to its relief structure.

[0101] It should also be appreciated that the configurations presentedin FIGS. 3-6 are not limited to the particular multi-layeredconfigurations presented in these figures. Although it may be preferableto have the relief structure be axially aligned with the anchor locationbetween the various structural layers of the second coupling at itsproximal end, such need not be the case (e.g., these anchor locationsmay be disposed different distances from the central, longitudinalreference axis 99 of the displacement multiplier 44). Moreover, theembodiments of FIGS. 2-6 are not limited to surface micromachinedconfigurations. What is of primary importance in the configurations ofFIGS. 2-6 is the inclusion of a relief structure that desirably modifiesthe torque and forces delivered to the remainder of the displacementmultiplier to reduce the amount that the displacement multiplierdeflects toward the underlying substrate. There also may becircumstances where the second coupling 52 may be eliminated altogetherfrom each of the embodiments of FIGS. 2-6. In this case, the tether 40and the relief structure could have the same thickness, and the reliefstructure would provide the function of transferring the forces from thetether 40 to both sides of the displacement multiplier 44 (relative toits central, longitudinal reference axis 99 as well).

[0102]FIG. 7 illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the amount of downward deflection of thedisplacement multiplier 44 when exposed to non-collinear forces. The“superscript” in relation to the displacement multiplier 44 ^(vi) ofFIG. 7 indicates that there is at least one difference from thedisplacement multiplier 44 of FIGS. 1A-B, principally in relation to howthe tether 40 interfaces with the displacement multiplier 44, versus howit interfaces with the displacement multiplier 44 ^(vi). Correspondingcomponents of the displacement multiplier 44 ^(vi) and the displacementmultiplier 44 are identified by common reference numerals.

[0103] The displacement multiplier 44 ^(vi) of FIG. 7 includes a reliefstructure 136 that is disposed on the opposite side (longitudinally) ofthe nodes 49 a, 49 b than the embodiments of FIGS. 2-6. The reliefstructure 136 includes a distal end 140 a and a proximal end 140 b.There are a number of basic differences between the configuration ofFIG. 7 and the configurations of FIGS. 2-6. First is that the tether 40extends along the central, longitudinal reference axis 99 of thedisplacement multiplier 44 ^(vi) beyond the longitudinal location of thenodes 49 a, 49 b in the case of the displacement multiplier 44 ^(vi),whereas the end of the tether 40 is spaced from the nodes 49 a, 49 b indirection of the elevator 20 in the case of the embodiments of FIGS.2-6. The tether 40 also interconnects with the proximal end 140 b of therelief structure 136 in the case of the FIG. 7 embodiment, whereas thetether 40 interconnects with the distal end of the relief structure ineach of the embodiments of FIGS. 2-6. Another is that the two sides ofthe relief structure 136 (one side being disposed on one side of thecentral, longitudinal reference axis 99 of the displacement multiplier44 ^(vi) and the other side being disposed on the other side of the axis99) are not interconnected by a structural cross member at its distalend 140 a, unlike the embodiments of FIGS. 2-6. The distal end 140 a ofthe relief structure 136 is also disposed along the central,longitudinal reference axis 99 of the displacement multiplier 44 ^(vi)at least generally at the nodes 49 a, 49 b. Finally, the reliefstructure 136 is formed from multiple structural layers (layers 104,108, and 112 in the illustrated embodiment) that may be pinned oranchored to each other in any appropriate manner. Generally, theconfiguration of the relief structure 136 and how the relief structure136 is interconnected with the remainder of the displacement multiplier44 ^(vi) reduces the magnitude of the torque that is exerted on thedisplacement multiplier 44 ^(vi) at least generally about an axis thatextends through the nodes 49 a, 49 b as a result of the existence of theabove-noted vertical force component.

[0104]FIG. 8 illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the potential for undesired contact withan underlying portion of the system due to the existence ofnon-collinear forces. Generally, the MEM system 150 includes adisplacement multiplier 168 that is mounted on (e.g., pinned oranchored) a displacement multiplier frame 152, that in turn is movablyinterconnected with the substrate 8. In one embodiment, the displacementmultiplier frame 152 is a more rigid structure than the displacementmultiplier 168, and in another embodiment is sufficiently rigid suchthat there is no substantial (or intended) flexure of the same whenexposed to the types of forces that are contemplated during normaloperation of the microelectromechanical system 150. Components of theframe 152 include a pair of frame sections 156 a, 156 c that aredisposed on opposite sides of and preferably equally spaced from acentral, longitudinal reference axis 170 of the displacement multiplier168. A displacement multiplier frame section 156 b extends betweeninterconnects the frame sections 156 a, 156 c at one end thereof, andthereby is disposed at least generally transverse to the central,longitudinal reference axis 170 of the displacement multiplier 168. Inthe illustrated embodiment, the displacement multiplier frame 152 is atleast generally U-shaped. Other configurations may be appropriate. Whatis of relevance is having at least a portion of a frame that is able tomove away from the substrate 8 (e.g., via a pivoting action or the like)when the displacement multiplier 168 mounted thereon is exposed tonon-collinear forces (and including where at least one of these forceshas a vertical force component).

[0105] One way for movably interconnecting the displacement multiplierframe 152 with the substrate 8 is via a plurality of frame flexures orcompliant members 160 that extend between the frame section 156 b and aplurality of frame anchors 164 that are fixed relative to the substrate8. These frame flexures 160 are less rigid (e.g., more flexible) thanthe displacement multiplier frame 152. The frame flexures 160 are theonly interconnection between the displacement multiplier frame 152 andthe substrate 8. Therefore, distal ends 158 of the displacementmultiplier frame 152 are able to move at least generally away from thesubstrate 8 by a flexing of the frame flexures 160 (e.g., by apivoting-like action of the displacement multiplier frame 152 about anaxis that is at least generally transverse to the central, longitudinalreference axis 170 of the displacement multiplier 168 and that extendsthrough the anchors 164).

[0106] The displacement multiplier 168 is defined by a plurality ofbeams 180 and is interconnected to the displacement multiplier frame 152at four anchor locations 184. An output coupling 176 of any appropriateconfiguration is disposed at one end of the displacement multiplier 168and may be interconnected with an appropriate load (e.g., the tether 40of the positioning assembly 4 of FIGS. 1A-B), while an input coupling174 of any appropriate configuration is disposed at the other end of thedisplacement multiplier 168 and may be interconnected with anappropriate motive source (e.g., the actuator 64 of the positioningassembly 4). Application of a force to the input coupling 174 of thedisplacement multiplier 168 so as to longitudinally move the inputcoupling 174 relative to the central, longitudinal reference axis 170 inthe direction of the arrow A will cause various portions of thedisplacement multiplier 168 to pivot in an at least generallypredetermined manner, and so as to also longitudinally move the outputcoupling 176 of the displacement multiplier 168 relative to the central,longitudinal reference axis 170 in the direction of the arrow B.

[0107] When the forces exerted on the input coupling 174 and the outputcoupling 176 are collinear, the various beams 180 of the displacementmultiplier 168 will be at least generally disposed within a plane thatis at least generally parallel with the substrate 8. The frame 152 willalso be disposed at least generally parallel with the substrate 8.However, when the forces exerted on the input coupling 174 and theoutput coupling 176 are not collinear (e.g., when output coupling 176 ofthe displacement multiplier 168 is exposed to a vertical forcecomponent, such as when the tether 40 moves the apex 22 of the elevator20 relative to the substrate 8 via a lateral movement of the actuator64), the distal ends 158 of the displacement multiplier frame 152 willmove relative to the substrate 8 to address this condition and reducethe potential for undesired contact between the displacement multiplier168 and the substrate 8. This again is realized by a pivoting-likeaction of the frame 152 relative to the substrate 8 and at leastgenerally about an axis that extends through the anchors 164 or oneparallel thereto. This then disposes the frame 152 at an angle relativeto the substrate 8. Moreover, the plurality of beams 180 of thedisplacement multiplier 168 will also continue to be at least generallydisposed within a common plane, but this common plane will now bedisposed at an angle relative to the substrate 8.

[0108] In order to reduce the magnitude of the vertical force componentthat is transmitted to the input coupling 174, and thereby anymicrostructure that may be interconnected therewith (e.g., the actuator64), at least one doubly clamped beam 192 is utilized by themicroelectromechanical system 150. Stated another way, any such doublyclamped beam 192 at least assists in the redirection of the force thatis exerted on the output coupling 176 so as to be at least generallycollinear with the force exerted on the input coupling 174. At least onedoubly clamped beam 192 is attached to the beams 180 k, 180 l of thedisplacement multiplier 168 that are disposed on opposite sides of thecentral, longitudinal reference axis 170 of the displacement multiplier168 and that are attached to the input coupling 174 of the displacementmultiplier 168. Each doubly clamped beam 192 is appropriately fixed tothe respective beam 180 k, 180 l of the displacement multiplier 168, andfurther is interconnected with the substrate 8 on both sides of therespective beam 180 k, 180 l via an anchor 196. As such, it should beappreciated that the inclusion of the doubly clamped beams 192constrains upward motion of the beams 180 k, 180 l when the outputcoupling 176 of the displacement multiplier 168 is exposed to a verticalforce component. This then reduces the amount of the vertical forcecomponent that is transferred to any microstructure that isinterconnected with the input coupling 174 of the displacementmultiplier 168 (e.g., the actuator 64). Reducing the amount of anyvertical force component that is transferred to the actuator 64 wheninterconnected with the input coupling 174 of the displacementmultiplier 168 is desirable in that the actuator 64 moves laterallyrelative to the substrate 8, and such a vertical force component mayadversely affect one or more aspects of the operation of such anactuator 64.

[0109]FIG. 9A illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the potential for undesired contact withan underlying portion of the system due to the existence ofnon-collinear forces. Generally, the microelectromechanical system 198of FIG. 9A includes a displacement multiplier 212 that is mounted on(e.g., pinned or anchored) a displacement multiplier frame assembly 200,that in turn is movably interconnected with the substrate 8 in anyappropriate manner. Components of the frame assembly 200 include aplurality of individual frame sections 204 a-d. One end of each framesection 204 a-d is interconnected with the substrate 8 by a frame anchor208, while a distal end 206 of each frame section 204 a-d is notattached to the substrate 8 so as to be able to move at least generallyaway from or toward the substrate 8. In one embodiment, the framesections 204 a-d are fabricated by surface micromachining so as to bepre-stressed. That is, the plurality of frame sections 204 a-d arefabricated so as to be in a stressed condition. One or more retentionpins or the like may be attached to each of these frame sections 204 a-dso as to retain each of these frame sections 204 a-d in theirpre-stressed state, even after the microelectromechanical system 198 isreleased by the use of one or more release etchants. At the desiredtime, each of these retention pins may be ruptured (e.g., by providingan appropriate electrical signal thereto), such that the distal end 234of each frame section 204 a-d may move at least generally away from thesubstrate 8 in an attempt to reduce the magnitude of the internalstresses therewithin. For instance, the frame sections 204 a-d may be inan at least generally arcuate shape at this time, with the correspondingdistal end 206 having moved away from the substrate 8 while the oppositeend remain pinned to the substrate 8 at the corresponding anchor 208. Assuch, in the static state the plurality of beams 224 would be at leastgenerally disposed within a common reference plane that is disposed atan angle relative to the substrate 8.

[0110] In another embodiment, the individual frame sections 204 a-d ofthe embodiment of FIG. 9A are more rigid structures than thedisplacement multiplier 168, and in another embodiment are sufficientlyrigid such that there is no substantial (or intended) flexure of thesame when exposed to the types of forces that are contemplated duringnormal operation of the microelectromechanical system 198. In this case,the individual frame sections 204 a-d would be pivotally interconnectedwith the substrate 8 utilizing the anchors 208, and would therebyfunction similarly to the displacement multiplier frame 152 of the FIG.8 embodiment.

[0111] The displacement multiplier 212 of FIG. 9A is defined by aplurality of beams 224 and is interconnected to the displacementmultiplier frame assembly 200 at four anchor locations 226. In theillustrated embodiment, the displacement multiplier 212 is symmetricalrelative to a central, longitudinal reference axis 214. An outputcoupling 220 is disposed on this axis 214 at one end of the displacementmultiplier 212 and may be interconnected with an appropriate load (e.g.,the tether 40 of the positioning assembly 4 of FIGS. 1A-B), while aninput coupling 216 is disposed on this axis 214 at the other end of thedisplacement multiplier 212 and may be interconnected with anappropriate motive source (e.g., actuator 64 of the positioning assembly4). Application of a force to the input coupling 216 of the displacementmultiplier 212 so as to move the input section 216, in the direction ofthe arrow A and along the axis 214, will cause various portions of thedisplacement multiplier 212 to pivot in an at least generallypredetermined manner, and so as to also move the output coupling 220 inthe direction of the arrow B and along the axis 214 of the displacementmultiplier 212.

[0112] The output coupling 220 of the displacement multiplier 212 isdisposed at a higher elevation than the input coupling 216 of thedisplacement multiplier 212 in the case were the frame sections 204 a-dare “pre-stressed” or when the displacement multiplier 212 is otherwiseexposed to non-collinear forces at its input coupling 216 and outputcoupling 220. Stated another way, the displacement multiplier 212 isdisposed “out-of-plane” relative to the substrate 8 when the framesections 204 a-d are pre-stressed or when the displacement multiplier212 is exposed to non-collinear forces. This increases the clearance ofthe entirety of the displacement multiplier 212 from the substrate 8. Assuch, exposure of the displacement multiplier 212 to non-collinearforces at its input coupling 216 and output coupling 220 (for instance,when the output coupling 220 is exposed to a vertical force component,such as when the tether 40 pulls the apex 22 of the elevator 20 awayfrom the substrate 8) should not cause any contact between thedisplacement multiplier 212 and any underlying portion of the MEM system198.

[0113]FIG. 9B illustrates another embodiment for providing non-collinearforce compensation in a microelectromechanical system, including withoutlimitation in terms of reducing the potential for undesired contact withan underlying portion of the system due to exposure to non-collinearforces. The MEM system 227 of FIG. 9B includes a displacement multiplier240 that is mounted on (e.g., pinned or anchored) a displacementmultiplier frame assembly 228, that in turn is movably interconnectedwith the substrate 8. Components of the frame assembly 228 include aplurality of individual frame sections 232 a-d. One end of each framesection 232 a-d is interconnected with the substrate 8 by a frame anchor236, while a distal end 234 of each frame section 232 a-d is notattached to the substrate 8 so as to be able to move at least generallyaway from or toward the substrate 8. The frame sections 232 of the FIG.9B embodiment may be configured in any of the manners discussed above inrelation to the frame sections 204 of the FIG. 9A embodiment.

[0114] The displacement multiplier 240 is defined by a plurality ofbeams 256 and is interconnected to the displacement multiplier frameassembly 228 at four anchor locations 258. In the illustratedembodiment, the displacement multiplier 240 is symmetrical relative to acentral, longitudinal reference axis 242. An output coupling 248 isdisposed on this axis 242 at one end of the displacement multiplier 240and may be interconnected with an appropriate load (e.g., the tether 40of the positioning assembly 4 of FIGS. 1A-B), while an input coupling244 at the other end of the displacement multiplier 240 and may beinterconnected with an appropriate motive source (e.g., actuator 64 ofthe positioning assembly 4). Application of a force to the inputcoupling 244 of the displacement multiplier 240 so as to move the inputcoupling 244, in the direction of the arrow A and along the axis in 242,will cause various portions of the displacement multiplier 240 to pivotin an at least generally predetermined manner, and so as to also movethe output coupling 248 in the direction of the arrow B and along theaxis 242 of the displacement multiplier 240.

[0115] The output coupling 248 of the displacement multiplier 240 isdisposed at a higher elevation than the input coupling 244 of thedisplacement multiplier 240 in the case were the frame sections 232 a-dare “pre-stressed” or when the displacement multiplier 240 is otherwiseexposed to non-collinear forces at its input coupling 244 and its outputcoupling 248. Stated another way, the displacement multiplier 240 isdisposed “out-of-plane” relative to the substrate 8. This increases theclearance of the entirety of the displacement multiplier 240 from thesubstrate 8. As such, exposure of the displacement multiplier 240 tonon-collinear forces at its input coupling 244 and output coupling 248(for instance, when the output coupling 248 is exposed to a verticalforce component, such as when the tether 40 pulls the apex 22 of theelevator 20 away from the substrate 8) should not cause any contactbetween the displacement multiplier 240 and any underlying portion ofthe microelectromechanical system 227.

[0116] In order to reduce the magnitude of any vertical force componentthat is transmitted to the input coupling 244, and thereby anymicrostructure that may be interconnected therewith (e.g., actuator 64),at least one doubly clamped beam 264 is utilized by themicroelectromechanical system 227. Stated another way, any such doublyclamped beam 264 at least assists in the redirection of the forceexerted on the output coupling 248 so as to be at least generallycollinear with the force exerted on the input coupling 244. At least onedoubly clamped beam 264 is attached to the beams 256 k, 256 l of thedisplacement multiplier 240. These beams 256 k, 256 l are disposed onopposite sides of the central, longitudinal reference axis 242 of thedisplacement multiplier 240 and are attached to the input coupling 244of the displacement multiplier 240. Each doubly clamped beam 264 isattached to the respective beam 256 k, 256 l of the displacementmultiplier 240, and further is interconnected with the substrate 8 onboth sides of the respective beam 256 k, 256 l via an anchor 268. Assuch, the inclusion of the doubly clamped beams 264 constrains upwardmotion of the beams 256 k, 256 l when the output coupling 248 of thedisplacement multiplier 240 is exposed to a vertical force component.This then reduces the amount of the vertical force component that istransferred to the structure that is interconnected with the inputcoupling 244 of the displacement multiplier 240 (e.g., the actuator 64).Reducing the amount of any vertical force component that is transferredto the actuator 64 when interconnected with the input coupling 244 ofthe displacement multiplier 240 is desirable in that the actuator 64moves laterally relative to the substrate 8, and such a vertical forcecomponent may adversely affect one or more aspects of the operation ofsuch an actuator 64. Once again, the doubly clamped beams 264 may becharacterized as at least assisting in the redirection of the force thatis exerted on the output coupling 248 so as to be at least generallycollinear with the force being exerted on the input coupling 244.

[0117] One embodiment that may be utilized for realizing a pre-stressedcondition for the plurality of beams 204 or the plurality of beams 232is illustrated in FIGS. 9C-E. FIG. 9C illustrates a pre-stressed member580 during the fabrication process and prior to performing the etchrelease. As such, the pre-stressed member 580 in FIG. 9C is stillembedded within a sacrificial material 578. An anchor 588 structurallyinterconnects the pre-stressed member 580 and an underlying substrate576 that is used in the fabrication of the pre-stressed member 580 andother portions of a microelectromechanical system that includes thepre-stressed member 580. Any appropriate configuration may be utilizedfor the anchor 588 and the same may be disposed at any appropriatelocation along the pre-stressed member 580 so as to define a free end581 that is able to move at least generally away from or at leastgenerally toward the substrate 576.

[0118] The pre-stressed member 580 includes a core 582 that is encasedwithin a body 584. The core 582 and the body 584 are formed fromdifferent materials. In one embodiment, the core 582 of the pre-stressedmember 580 utilizes the same composition as the sacrificial material 578that is removed by the release etchant, while the body 584 is formedfrom an appropriate structural material for surface micromachiningapplications. As such, the core 582 is not removed by the releaseetchant due to the encasement that is provided by the body 584. In thisregard, the body 584 includes an upper wall 586 a, a lower wall 586 b,and an interconnecting sidewall 586 c that define an enclosed space thatcontains the core 582. In one embodiment, the upper wall 586 a and thelower wall 586 b are of different thicknesses.

[0119] When the sacrificial material 578 is removed by an appropriaterelease etchant and as illustrated in FIGS. 9D-E, the free end 581 ofthe pre-stressed member 580 moves at least generally away from thesubstrate 576. This movement is due to a stress gradient that existswithin the pre-stressed member 580 as a result of the encasement of thecore 582 within the body 584, as well as the upper wall 586 a and thelower wall 586 b of the body 584 being of different thicknesses. Thisstress gradient bends the free end 581 of the pre-stressed member 580out of the plane of the substrate 576 and at least generally about theanchor 588 to accommodate the stress gradient when the surroundingsacrificial material 578 is removed during the etch-release step. Thepre-stressed member 580 thereby in effect forms a compressed springwhich exerts an at least generally upwardly-directed force on anystructure interconnected therewith to at least attempt to move the sameaway from the substrate 576.

[0120] FIGS. 10A-B illustrates another embodiment for providingnon-collinear force compensation in a microelectromechanical system,including without limitation in terms of reducing the potential forundesired contact with an underlying portion of the system due toexposure to non-collinear forces. Generally, the MEM system 272 of FIGS.10A-B utilizes a displacement multiplier 276 that is mounted on (e.g.,pinned or anchored) the substrate 8 in a manner so as to allow at leastpart of the displacement multiplier 276 to move at least generally awayfrom the substrate 8 when the displacement multiplier 276 is exposed tonon-collinear forces and including where at least one of these forceshas a vertical force component. The displacement multiplier 276 isdefined by a plurality of beams 280 that are interconnected by aplurality of flex joints 284. In the illustrated embodiment, thedisplacement multiplier 276 is symmetrical relative to a central,longitudinal reference plane 282.

[0121] One end/end portion of each of the beams 280 c, 280 d isinterconnected with the substrate 8 by a flexure 292 and an anchor 288.Each flexure 292 is more flexible (i.e., less rigid) than itscorresponding beam 280 c, 280 d. Only two structural interconnectionsexist between the displacement multiplier 276 and the substrate 8.Generally, the displacement multiplier 276 is interconnected with thesubstrate 8 so that an output end 278 of the displacement multiplier 276is able to move at least generally away from or toward the substrate 8(depending upon the direction of the force acting on the output end278), typically along an at least generally arcuate path. Stated anotherway, an input end 286 of the displacement multiplier 276 is in effectpinned to the substrate 8 so as to allow the output end 278 to in effectmove at least generally about an axis that extends through the anchors288 by a bending of the flexures 292. Although the desired pivoting isrealized in the illustrated embodiment by anchoring the displacementmultiplier 272 to the substrate 8 at only two locations, it may bepossible to anchor the displacement multiplier 272 to the substrate 8 atmore than two locations and still realize the desired pivotal motion.For instance, the displacement multiplier 272 could be anchored to thesubstrate at two or more locations, so long as these anchor locationsare at least generally disposed along a common axis. It should beappreciated that the four structural interconnections between thedisplacement multiplier 44 and the substrate 8 that are used in the caseof the displacement multiplier 44 of FIGS. 1A-B would not allow for thissame type of desired pivotal movement.

[0122] An output beam 294 is disposed at least generally along acentral, longitudinal reference axis 282 at one end of the displacementmultiplier 276, is interconnected with the flex joint 284 b that isdisposed on this reference axis 282, and may be interconnected with anappropriate load (e.g., the tether 40 of the positioning assembly 4 ofFIGS. 1A-B). The output beam 294 could also actually be the tether 40.The displacement multiplier 276 also includes an input beam 296 that isdisposed at the opposite end of the displacement multiplier 276, that isinterconnected with flexure joint 284 e that is also disposed on thenoted reference axis 282, and that may be interconnected with anappropriate motive source (e.g., the actuator 64 of the positioningassembly 4). The input beam 296 could be in the form of a tether orcoupling that interconnects the displacement multiplier 276 with one ormore actuators.

[0123] It should be appreciated that application of a force to the inputbeam 296 so as to move the input beam 296 in a direction that is atleast generally parallel with the arrow “A” and along the plane 282,will cause various portions of the displacement multiplier 276 to pivotin at least a generally predetermined manner, so as to also move theoutput beam 294 in a direction that is at least generally parallel withthe arrow “B” and along the reference axis 282 of the displacementmultiplier 276. FIG. 10A illustrates the configuration of thedisplacement multiplier 276 before application of a motive force to theinput beam 296, while FIG. 10B illustrates the “collapsed” configurationof the displacement multiplier 276 during/after the application of theforce to the input beam 296.

[0124] In the event that the displacement multiplier 276 is not exposedto any vertical force component at its output end 278, the pivoting ofthe displacement multiplier 276 will be at least generally within aplane that is at least generally parallel with the substrate 8. Exposureof the output end 278 of the displacement multiplier 276 to a verticalforce component will still allow the displacement multiplier 276 to movefrom the general configuration of FIG. 10A to the general configurationof FIG. 10B to provide the general displacement multiplication/reductionor translation function. However, since the displacement multiplier 276is only interconnected with the substrate 8 along both sides of thereference axis 282 and at least toward the input end 286 of thedisplacement multiplier 276, the output beam 294 and the output end 278of the displacement multiplier 276 are both allowed to move at leastgenerally away from the substrate 8 when the vertical force component isdirected away from the substrate 8. This movement may be along anyappropriate path (e.g., along an arc) and in any orientation relative tothe substrate 8. Generally, the movement of the output beam 294 and theoutput end 278 of the displacement multiplier 276 at least generallyaway from the substrate 8 upon exposure of the output end 278 to avertical force component that is directed away from the substrate 8should significantly reduce the potential for any contact between thedisplacement multiplier 276 and any underlying portion of themicroelectromechanical system 272.

[0125] Another way of addressing the exposure of the output beam 294 toa vertical force component is through the use of one or more doublyclamped beams in relation to the input side of the displacementmultiplier 276. Such a configuration is presented by the MEM system 272′of FIG. 11. The “single prime” designation indicates that there is atleast one difference from the configuration presented in FIGS. 10A-B.This difference is the presence of at least one doubly clamped beam 300which is associated with the input beam 296 of the displacementmultiplier 276, which is illustrated in FIG. 11 as being interconnectedwith the actuator 64. Each beam 300 is attached to the input beam 296 ofthe displacement multiplier 276, and further is interconnected with thesubstrate 8 on both sides of input beam 296 via an anchor 302. As such,the inclusion of the doubly clamped beams 300 constrains upward motionof the input beam 296 when the output end 278/output beam 294 of thedisplacement multiplier 276 is exposed to a vertical force component.This then reduces the amount of the vertical force component that istransferred to the structure that is interconnected with the input beam296 of the displacement multiplier 272 (e.g., the actuator 64). Reducingthe amount of any vertical force component that is transferred to theactuator 64 when interconnected with the input beam 296 of thedisplacement multiplier 276 is desirable in that the actuator 64 moveslaterally relative to the substrate 8, and such a vertical forcecomponent may adversely affect one or more aspects of the operation ofthis actuator 64.

[0126]FIG. 12A presents an embodiment for a exerting a positioning forceon a microstructure that does not utilize a displacement multiplier, butwhich still compensates for non-collinear forces, including where atleast one of those forces has a vertical force component. Thepositioning assembly 304 generally includes an elevator 308 that isinterconnected with a pair of actuators 328 by a tether 336. Theelevator 308 is defined by a pair of elevation members 312. One end ofeach elevation members 312 is interconnected with a flexure 320, that inturn is interconnected with an anchor 324 attached to/extending upwardlyfrom a substrate 306. The opposite ends of the elevation members 312intersect to define a free end or apex 316 of the elevator 308. Theelevation members 312 are also interconnected by an intermediate crossbeam 314 at a location that is spaced from its free end 316.

[0127] The pair of lateral actuators 328 are disposed on opposite sidesof the elevator 308, are interconnected with the substrate 306 in anappropriate manner to allow the same to move laterally relative to thesubstrate 306, and are interconnected by a common output yoke 332. Theoutput yoke 332 is a rigid structure that is movably interconnected withthe substrate 306 by a plurality of flexures 356. At least one flexure356 is disposed on each side out of the output yoke 332 and is fixed tothe substrate 306 by an anchor 360. A flexible yoke interconnect 340extends from the output yoke 332 and is interconnected with the tether336. The opposite end of the tether 336 is appropriately attached to thecross beam 314. Since the cross beam 314 is spaced from the free end 316of the elevator 308, this reduces the amount of lateral displacement ofthe actuators 328 that is required to move the free end 316 of theelevator 312 relative to the substrate 306 a predetermined distance.Moving the cross beam 314 further away from the free end 316 of theelevator 308 will further reduce the amount of lateral movement of theactuators 328 that is required to displace the free end 316 of theelevator 308 this same predetermined distance relative to the substrate306.

[0128] Movement of the actuators 328 in the direction that is parallelwith the direction of the arrow A in FIG. 12A exerts a pulling force onthe tether 336, that in turn pivots the elevator 308 at least generallyabout an axis than extends through the anchors 324 that interconnect theelevator 308 with the substrate 306. This pivoting action is by abending of the flexures 320. The forces acting on the opposite ends ofthe tether 336 are thereby not collinear. The force acting on that endof the tether 336 that is attached to the elevator 308 includes avertical force component. This vertical force component is exerted onthe flexible yoke interconnect 340, and is transferred to the outputyoke 332 and each of the actuators 328. In order to at least reduce themagnitude of the vertical force component that is transferred to theactuators 328, the positioning assembly 304 utilizes at least one doublyclamped beam 352 that is attached to the tether 336, the yokeinterconnect 340, or both, and that is fixed to the substrate 306 by apair of anchors 348. At least one anchor 348 is disposed on each side ofthe tether 336.

[0129] In the illustrated embodiment, there is a single doubly clampedbeam 352. This doubly clamped beam 352 is located near the output yoke332. This arrangement allows the elevator 308 to be placed in closeproximity to the output yoke 332, which in turn results in an efficientuse of space on the substrate. In any case, a vertical force that isexerted on the end of the tether 336 that is attached to the elevator308 is vertically restrained by the doubly clamped beam 352, that inturn reduces the magnitude of the vertical force component that istransmitted to the output yoke 332 and thereby the actuators 328.Multiple doubly clamped beams 352 could be utilized as well.

[0130]FIG. 12B presents another embodiment for exerting a positioningforce on a microstructure that does not use a displacement multiplier,but which still compensates for non-collinear forces, including where atleast one of the forces has a vertical force component. The embodimentsof FIGS. 12A and 12B are similar, and similar components thereby use thesame reference numerals. Those components/assemblies that are differentin at least one respect are identified by a “single prime” designation.The primary difference between the positioning assembly 304′ of FIG. 12Band the positioning assembly 304 of FIG. 12A is in relation to the yokeinterconnect 340′ and the interconnection of the same with the tether336. The yoke interconnect 340′ is a more rigid structure in the case ofthe FIG. 12B embodiment. A post 364 is anchored to and extends upwardlyfrom the yoke interconnect 340′ in longitudinally offset relation to thedoubly clamped beam 352. Stated another way, the post 364 and the crossbeam 314, which interconnect with opposite ends of the tether 336, aredisposed on opposite sides of the doubly clamped beam 352. This alsodisposes the point of interconnection closer to an axis that extendsthrough the pair of flexures 356 that interconnect the output yoke 332with the substrate 306. Since the length of the moment arm is reduced incomparison to the FIG. 12A in embodiment, the magnitude of the momentexperienced by the flexures 356 is reduced in the case of the FIG. 12Bembodiment compared to the FIG. 12A embodiment.

[0131] Another option for compensating for the existence ofnon-collinear forces when using a displacement multiplier is presentedin FIG. 13. The microelectromechanical system 370 of FIG. 13 includes adisplacement multiplier 376. This displacement multiplier 376 is definedby a plurality of beams 380 that are interconnected in a manner so as toallow for a desired degree of lateral movement of an input yoke 388 andoutput yoke 384 of the displacement multiplier 376. This again isprovided by a flexing of at least those beams 380 that are fixed to ananchor 398, that is in turn fixed to the substrate 368. Four anchors 386are utilized by the displacement multiplier 376.

[0132] A plurality of cavities or wells 372 are formed in the substrate368 under portions of the displacement multiplier 376 that would tend todeflect the most toward the substrate 368 when the forces exerted on theoutput yoke 384 and the input yoke 388 are not collinear (for instance,when the output yoke 384 is exposed to a vertical force component).Generally, a cavity or well 372 within the substrate 368 is formed underthose portions of the displacement multiplier 376 that will tend todeflect toward the substrate 368 the most when the displacementmultiplier 376 is exposed to non-collinear forces, including where oneof these forces has a vertical force component. Stated another way, anappropriately sized cavity 372 is formed in the substrate 368 underthose portions of the displacement multiplier 376 that are susceptibleto contacting the substrate 368 when exposed to the magnitudes ofnon-collinear forces that would be anticipated during normal operationof the microelectromechanical system 370. One or more doubly clampedbeams (not shown) of the type discussed above could be attached to theinput yoke 388 or an interconnecting structure between the input yoke388 and a microstructure that exerts a load on the input yoke 388 (e.g.,one or more actuators). Preferably, the output yoke 384 is configured inthe manner of any of the relief structures of FIGS. 2-7 that werediscussed above.

[0133] Another option for compensating for the existence ofnon-collinear forces when using a displacement multiplier is presentedin FIG. 14. The microelectromechanical system 408 of FIG. 14 includes adisplacement multiplier 402. This displacement multiplier 402 is definedby a plurality of beams 420 that are interconnected in a manner so as toallow for a desired degree of lateral movement of an input yoke 412 andan output yoke 404 of the displacement multiplier 402. This again isprovided by a flexing of at least those beams 420 that are fixed to ananchor 424, that is in turn fixed to a substrate 400. In the case of thedisplacement multiplier 402, the input yoke 412 and the output yoke 404move in opposite directions. The input yoke 412 moves at least generallyin the direction of the arrow A, while the output yoke 404 moves atleast generally in the direction of the arrow B.

[0134] Compensation for non-collinear forces that are exerted on theinput yoke 412 and the output yoke 404 is provided for the displacementmultiplier 402 by the selection of location of at least some of theanchors 424 of the displacement multiplier 402 to the substrate 400.Nodes 416 a, 416 b are disposed on opposite sides of a central,longitudinal reference axis 416 of the displacement multiplier 402, andare the portions of the displacement multiplier 402 that are disposedfurthest from this axis 416. A lateral reference axis 418 extendsthrough the nodes 416 a, 416 b, and in the illustrated embodiment theaxis 418 is perpendicular to the central, longitudinal reference axis416, although this may not necessarily be the case for allconfigurations of the displacement multiplier 402. Generally,compensation for non-collinear forces being exerted on the input yoke412 and the output yoke 404 is provided in the case of the FIG. 14embodiment by having all of the anchors 424 disposed at a longitudinalposition that is no closer to the output yoke 404 than the referenceaxis 418. Another characterization is that all of the anchors 424 aredisposed at a longitudinal position that is no further from thelongitudinal position of the input section 412 than the longitudinalposition of the reference axis 418. Having the anchors 424 of thedisplacement multiplier 402 to the substrate 400 satisfy one or both ofthe noted characterizations reduces the potential for nodes 416 a, 416 bdeflecting an amount so as to contact the substrate 400 during normaloperation of the microelectromechanical system 408. One or more doublyclamped beams (not shown) of the type discussed above could be attachedto the input yoke 412 or an interconnecting structure between the inputyoke 412 and a microstructure that exerts a load on the input yoke 412(e.g., one or more actuators).

[0135] Another option for compensating for the existence ofnon-collinear forces when using a displacement multiplier is presentedin FIGS. 15A-B. The microelectromechanical system 474 includes adisplacement multiplier 456. This displacement multiplier 456 of FIGS.15A-B is defined by a plurality of beams 460 that are interconnected ina manner so as to allow for a desired degree of lateral movement of aninput yoke 468 and an output yoke 464 of the multiplier microstructure456. This again is provided by a flexing of at least those beams 460that are fixed to an anchor 484, that is in turn fixed to a substrate428.

[0136] Compensation for non-collinear forces that are exerted on theinput yoke 468 and the output yoke 464 is provided for the displacementmultiplier 456 in the form of a recess or cavity 476 that is formed inthe substrate 428 under at least a substantial portion of thedisplacement multiplier 456. A base 478 defines the bottom of the cavity476, and a wall 480 defines a perimeter of this cavity 476. In theillustrated embodiment, the wall 480 also extends upwardly from theportion of the substrate 428 that is adjacent to the cavity 476 as well,although such is not required.

[0137] The anchors 484 for the displacement multiplier 456 are disposedat least generally proximate the wall 480 of the cavity 476. The onlyportion of the displacement multiplier 456 of FIGS. 15A-B that is notdisposed entirely within the cavity 476 are the interconnectingstructures between the beams 460 of the displacement multiplier 456 andthe corresponding anchors 484. Another characterization of thedisplacement multiplier 456 in relation to the cavity 476 is that allfree ends 458 of the displacement multiplier 456 are disposed within thecavity 476. The free ends 458 are those portions of the displacementmultiplier 456 that are cantilevered of sorts and that could deflectdown and engage the underlying structure, and thereby include both theinput yoke 468 and the output yoke 464. As such, the “free ends” 458obviously excludes those ends of the beams 460 of the displacementmultiplier 456 that are attached to an anchor 484.

[0138] The purpose of the cavity 476 is to increase the spacing betweenthe various beams 460 of the displacement multiplier 456 and theunderlying structure (the base 478 in the FIGS. 15A-B embodiment), or atleast the spacing between the “free ends” 458 and the base 478, toreduce the potential for contact therebetween when the displacementmultiplier 456 is exposed to non-collinear forces at its input yoke 468and its output yoke 464. In one embodiment, each free end 458 of thedisplacement multiplier 456 is separated from the base 478 of the cavity476 by a distance of at least about 7 microns. One or more doublyclamped beams (not shown) of the type discussed above could be attachedto the input yoke 468 or an interconnecting structure between the inputyoke 468 and a microstructure that exerts a load on the input yoke 468(e.g., one or more actuators). Preferably, the output yoke 464 isconfigured in the manner of any of the relief structures of FIG. 2-7that were discussed above.

[0139] Further details regarding the cavity 476 of FIGS. 15A-B arepresented in FIG. 16A. In the case where the microelectromechanicalsystem 474 is formed at least in part by surface micromachining, thesubstrate 428 may be characterized as being defined by a wafer material430, an overlying oxide layer 432, and an overlying nitride layer 436 asillustrated in FIG. 16A. The oxide layer 432 and the nitride layer 436may collectively define a dielectric layer for themicroelectromechanical system 474 that includes the displacementmultiplier 456. In any case, one way in which the cavity 476 and itsperimeter wall 480 may be defined is by patterning the nitride layer 436and oxide layer 432 to define a similarly shaped (to the desired cavity476), but larger cavity. This cavity would extend down through thenitride layer 436 and the oxide layer 432 to an exposed surface 496 ofthe wafer material 430. The perimeter of this cavity would then bedefined by at least an edge surface 438 of the nitride layer 436 and byan edge surface 434 of the oxide layer 432. When themicroelectromechanical system 474 is released, the system 474 is exposedto a release etchant to remove at least certain sacrificial oxidematerial. This release etchant would also etch away at the oxide layer432 if access is provided thereto via the edge surface 434. This wouldnot be desirable.

[0140] In order to protect the oxide layer 432 during the above-notedrelease etch, and as illustrated in FIG. 16A a relatively thinpolysilicon layer P₀ is deposited on the nitride layer 436, along theedge surfaces 438 and 434 of the nitride layer 436 and oxide layer 432,respectively, and on the exposed surface 496 of the wafer material 430.Thereafter, this polysilicon layer P₀ may be patterned to removerelevant portions thereof that are disposed outside of the cavity 476,although such is not required for purposes of reducing the potential forcontact between the displacement multiplier 456 and the base 478 of thecavity 476. The polysilicon layer P₀ could also be patterned to removethe polysilicon layer P₀ to expose the surface 496 of the wafer material430 for the base 478 of the cavity 476, provided that the polysiliconlayer P₀ still defines the exposed surface of the wall 480 (i.e., suchthat the polysilicon layer P₀ still seals the previously exposed edgesurface 434 of the oxide layer 432).

[0141] Additional polysilicon layers may be used to reduce the potentialfor the release etchant having access to the exposed edge surface 434 ofthe oxide layer 432 and as also illustrated in FIG. 16A. Polysiliconlayers P₁ and P₂ may be sequentially deposited and patterned (with anintermediate layer of sacrificial material being deposited/patternedtherebetween in accordance with conventional surface micromachiningtechniques) into the configuration presented in FIG. 16A to not onlydefine a lower portion of the illustrated anchor 484, but to alsoincrease the thickness of polysilicon that seals the previously exposededge surface 434 of the oxide layer 432. Thereafter, polysilicon layersP₃ and P₄ may be sequentially deposited and patterned (with anintermediate layer of sacrificial material being deposited/patternedtherebetween in accordance with surface micromachining techniques) intothe configuration presented in FIG. 16A to define an upper portion ofthe illustrated anchor 484 and also to define the various beams 460 ofthe displacement multiplier microstructure 456. That is, the beams 460of the displacement multiplier microstructure 456 may be defined by apair of vertically spaced and structurally interconnected polysiliconlayers P₃ and P₄ in the embodiment of FIG. 16A.

[0142] Instead of disposing the anchors for a displacement multiplieroutside of a cavity in which the displacement multiplier is positionedto increase the clearance below the displacement multiplier for purposesof compensating for non-collinear forces, these anchors may bepositioned entirely within the cavity along with the rest of thedisplacement multiplier microstructure. FIG. 16B illustrates such aconfiguration where all of the anchors 484 ^(i) for a displacementmultiplier (not shown, but having its beams formed from the types ofpolysilicon layers P₃ and P₄ illustrated in FIG. 16A discussed above)are located within the cavity 476 ^(i), along with the entirety of thedisplacement multiplier. Like the embodiment of FIG. 16A, both thepolysilicon layers P₀ and P₁ seal the edge surface 434 of the oxidelayer 432. However, since the anchor 484 ^(i) is entirely disposedwithin the cavity 476 ^(i) in the case of the FIG. 16B embodiment, theedge surface 434 of the oxide layer 432 is annular, as are the portionsof the polysilicon layers P₀ and P₁ that seal this edge surface 434.Another distinction between the FIGS. 16A and 16B embodiments is thatthe configuration of the anchor 484 ^(i) is different than that of theanchor 484 illustrated in FIG. 16A.

[0143] One benefit provided by the configurations of FIGS. 16A and 16Bis that sealing the edge surface 434 of the oxide layer 432 withmaterial from the polysilicon layers P₀ and P₁ reduces the potential forthe release etchant gaining access to the oxide layer 432 through theedge surface 434. In some cases, it may be acceptable to seal the edgesurface 434 of the oxide layer 432 with only material from thepolysilicon layer P₀. This variation is presented in FIG. 16C. As in theFIG. 16B embodiment, the variation of FIG. 16C includes a cavity 476^(ii) that contains the entirety of the displacement multiplier (notshown, but having its beams formed from the types of polysilicon layersP₃ and P₄ illustrated in FIG. 16A) and all of its anchors 484 ^(ii) tothe substrate 428. Sealing of the edge surface 434 of the oxide layer432 using only the material from the polysilicon layer P₀ could also beemployed by the configuration presented in FIG. 16A.

[0144] In some cases the microelectromechanical system will not includean oxide layer between the nitride layer 436 and the wafer material 430.In this case, it is not necessary to seal a surface of an oxide layerthat is exposed during formation of a cavity for increasing clearancefor a displacement multiplier microstructure. This is the variationpresented in FIG. 16D. As in the FIGS. 16B-C embodiments, the variationof FIG. 16D includes a cavity 476 ^(iii) that contains the entirety ofthe displacement multiplier (not shown, but having its beams formed fromthe types of polysilicon layers P₃ and P₄ illustrated in FIG. 16A) andall of its anchors 484 ^(iii) to the substrate 428. These sameprinciples would be equally applicable to the configuration presented inFIG. 16A.

[0145] Any of the above-described embodiments that address the existenceof non-collinear forces may be used in any combination with each other.For instance, in one embodiment any of the embodiments of FIGS. 2-7 maybe used in combination with any of the embodiments of FIGS. 13, and15A-16D.

[0146] The foregoing description of the present invention has beenpresented for purposes of illustration and description. Furthermore, thedescription is not intended to limit the invention to the form disclosedherein. Consequently, variations and modifications commensurate with theabove teachings, and skill and knowledge of the relevant art, are withinthe scope of the present invention. The embodiments describedhereinabove are further intended to explain best modes known ofpracticing the invention and to enable others skilled in the art toutilize the invention in such, or other embodiments and with variousmodifications required by the particular application(s) or use(s) of thepresent invention. It is intended that the appended claims be construedto include alternative embodiments to the extent permitted by the priorart.

What is claimed is:
 1. A microelectromechanical system, comprising: asubstrate; a first load microstructure movably interconnected with saidsubstrate for movement at least substantially along a first path; asecond load microstructure movably interconnected with said substrate; acoupling assembly microstructure interconnecting said first and secondload microstructures and that comprises means for transmitting a forcethat is exerted on said coupling assembly microstructure by at least oneof said first and second load microstructures to achieve both first andsecond conditions, wherein said first condition is that said force istransmitted to said first load microstructure at least generally alongsaid first path, and wherein said second condition is that no portion ofsaid coupling assembly microstructure is deflected into contact with anyother portion of said microelectromechanical system.
 2. Amicroelectromechanical system, as claimed in claim 1, wherein: saidfirst load microstructure comprises an actuator microstructure.
 3. Amicroelectromechanical system, as claimed in claim 1, wherein: saidfirst path is at least substantially linear.
 4. A microelectromechanicalsystem, as claimed in claim 1, wherein: said first path is at leastgenerally parallel with said substrate.
 5. A microelectromechanicalsystem, as claimed in claim 1, wherein: said second load microstructureis selected from the group consisting essentially of a mirrormicrostructure, a lens, a diffraction element, and an attenuator.
 6. Amicroelectromechanical system, as claimed in claim 1, wherein: saidfirst and second load microstructures are disposed at the same elevationwithin said microelectromechanical system.
 7. A microelectromechanicalsystem, as claimed in claim 1, wherein: said first and second loadmicrostructures are disposed at different elevations within saidmicroelectromechanical system.
 8. A microelectromechanical system, asclaimed in claim 1, wherein: a direction of said force at said secondload microstructure is at least generally parallel with said first path.9. A microelectromechanical system, as claimed in claim 8, wherein: saidfirst and second load microstructures are disposed at the same elevationin said microelectromechanical system.
 10. A microelectromechanicalsystem, as claimed in claim 8, wherein: said first and second loadmicrostructures are disposed at a different elevation in saidmicroelectromechanical system.
 11. A microelectromechanical system, asclaimed in claim 1, wherein: a direction of said force at said secondload microstructure is other than parallel with said first path.
 12. Amicroelectromechanical system, as claimed in claim 11, wherein: saidfirst and second load microstructures are disposed at the same elevationin said microelectromechanical system.
 13. A microelectromechanicalsystem, as claimed in claim 11, wherein: said first and second loadmicrostructures are disposed at a different elevation in saidmicroelectromechanical system.
 14. A microelectromechanical system, asclaimed in claim 1, wherein: said second load microstructure is movablyinterconnected with said substrate for movement at least substantiallyalong a second path.
 15. A microelectromechanical system, as claimed inclaim 14, wherein: said second path comprises a component that is atleast substantially normal to said substrate.
 16. Amicroelectromechanical system, as claimed in claim 14, wherein: saidsecond path comprises a component that is at least substantiallyparallel to said substrate.
 17. A microelectromechanical system, asclaimed in claim 14, wherein: said second path is at least substantiallylinear.
 18. A microelectromechanical system, as claimed in claim 14,wherein: said second path is at least substantially arcuate.
 19. Amicroelectromechanical system, as claimed in claim 14, wherein: saidfirst and second load microstructures are disposed at the same elevationin said microelectromechanical system and all movement of said first andsecond load microstructures along said first and second paths,respectively, is within a plane that is at least substantially parallelwith said substrate.
 20. A microelectromechanical system, as claimed inclaim 14, wherein: said second load microstructure is pivotallyinterconnected with said substrate such that a portion of said secondload microstructure moves at least generally away from said substratealong an at least generally arcuate path.
 21. A microelectromechanicalsystem, as claimed in claim 14, wherein: said first and second loadmicrostructures are disposed at a different elevation in saidmicroelectromechanical system.
 22. A microelectromechanical system, asclaimed in claim 21, wherein: all movement of said first and second loadmicrostructures along said first and second paths, respectively, iswithin a plane that is at least substantially parallel with saidsubstrate.
 23. A microelectromechanical system, as claimed in claim 1,wherein: said coupling assembly microstructure comprises an elevatormicrostructure interconnected with said second load microstructure and atether disposed between said elevator microstructure and said firstactuator microstructure.
 24. A microelectromechanical system, as claimedin claim 1, wherein: said means for transmitting in relation to saidfirst condition comprises a pivotless compliant microstructure, whereinsaid pivotless compliant microstructure comprises input and an outputsections, wherein said input section is interconnected with said firstload microstructure and said output section is interconnected with saidsecond load microstructure.
 25. A microelectromechanical system, asclaimed in claim 24, wherein: said pivotless compliant microstructurecomprises a relief structure disposed between and interconnecting saidpivotless compliant microstructure and said coupling assemblymicrostructure, wherein said means for transmitting in relation to saidsecond condition further comprises said relief structure.
 26. Amicroelectromechanical system, as claimed in claim 24, wherein: saidmeans for transmitting further in relation to said second conditioncomprises a frame assembly microstructure pivotally interconnected withsaid substrate, wherein said pivotless compliant microstructure ismounted on said frame assembly microstructure.
 27. Amicroelectromechanical system, as claimed in claim 26, wherein: saidframe assembly microstructure is rigid and of one-piece construction.28. A microelectromechanical system, as claimed in claim 26, wherein:said frame assembly microstructure comprises a plurality of individualframe member microstructures that are each individually pivotallyinterconnected with said substrate, wherein each frame membermicrostructure is prestressed so as to move away from said substratewithout an application of any external force to said frame membermicrostructure.
 29. A microelectromechanical system, as claimed in claim24, wherein: said pivotless compliant microstructure is interconnectedwith said substrate by a first pivotable connection, wherein said meansfor transmitting in relation to said second condition comprises saidfirst pivotable connection.
 30. A microelectromechanical system, asclaimed in claim 24, wherein: said means for transmitting in relation tosaid second condition further comprises at least one cavity formed insaid substrate under at least a portion of said pivotless compliantmicrostructure.
 31. A microelectromechanical system, as claimed in claim24, wherein: said means for transmitting in relation to said secondcondition further comprises a cavity formed in said substrate, whereinan entirety of said pivotless compliant microstructure is disposedwithin said cavity.
 32. A microelectromechanical system, as claimed inclaim 24, wherein: said pivotless compliant microstructure is anchoredto said substrate at least at four anchor locations, wherein said meansfor transmitting in relation to said second condition comprises alocation of at least two of said anchor locations.
 33. Amicroelectromechanical system, as claimed in claim 1, wherein: saidmeans for transmitting comprises at least one doubly clamped beam.
 34. Amicroelectromechanical system, as claimed in claim 33, wherein: said atleast one doubly clamped beam comprises a plurality of vertically spacedand rigidly interconnected structural layers.
 35. Amicroelectromechanical system, as claimed in claim 1, wherein said meansfor transmitting in relation to said first condition comprises: apivotless compliant microstructure interconnected with said substrateand comprising input and output sections that are both movable relativeto said substrate within a lateral dimension that is at least generallyparallel with said substrate, wherein said second load microstructure isinterconnected with said output section of said pivotless compliantmicrostructure and said input section of said pivotless compliantmicrostructure is interconnected with said first load microstructure,wherein a movement of said first load microstructure relative to saidsubstrate along said first path displaces said input section of saidpivotless complaint microstructure a first distance within said lateraldimension, and that in turn displaces said output section of saidpivotless complains microstructure a second distance in said lateraldimension, wherein said first and second distances are selected from thegroup consisting essentially of equal and unequal magnitudes.
 36. Amicroelectromechanical system, as claimed in claim 35, wherein: saidoutput section is formed from a single structural layer by surfacemicromachining and a remainder of said pivotless compliantmicrostructure is formed from at least two vertically spaced structurallayers by surface micromachining and that are anchored to each other ata plurality of locations.
 37. A microelectromechanical system, asclaimed in claim 35, wherein: a configuration of said output section andhow said output section interconnects with a remainder of said pivotlesscompliant microstructure comprises said means for transmitting inrelation to said second condition.
 38. A microelectromechanical system,as claimed in claim 35, wherein: said pivotless compliant microstructurecomprises first and second beam microstructures that are attached tosaid output section of said pivotless compliant microstructure at afirst location, and further extend away from said output section of saidpivotless compliant microstructure in at least generally oppositedirections, wherein said output section comprises first and second ends,and wherein said first location is disposed at an intermediate locationbetween said first and second ends.
 39. A microelectromechanical system,as claimed in claim 35, wherein: said pivotless compliant microstructurecomprises first and second beam microstructures that are attached tosaid output section of said pivotless compliant microstructure at afirst longitudinal location, and further extend away from said outputsection of said pivotless compliant microstructure in at least generallyopposite directions, wherein said output section extends from said firstlongitudinal location at least generally toward but not to said inputsection of said pivotless compliant microstructure.
 40. Amicroelectromechanical system, as claimed in claim 35, wherein: saidmeans for transmitting in relation to said second condition comprises arigid frame microstructure pivotally interconnected with said substrateand said pivotless compliant microstructure being mounted on said framemicrostructure.
 41. A microelectromechanical system, as claimed in claim40, wherein: said pivotless compliant microstructure comprises a firstportion of said coupling assembly microstructure, wherein a secondportion of said coupling assembly microstructure is disposed betweensaid input section of said pivotless compliant microstructure and saidfirst load microstructure, and wherein said means for transmitting inrelation to said first condition comprises at lease one doubly clampedbeam that is attached to said second portion of said coupling assemblymicrostructure and that is anchored to said substrate on opposite sidesof second portion of said coupling assembly microstructure.
 42. Amicroelectromechanical system, as claimed in claim 35, wherein: saidmeans for transmitting in relation to said second condition comprises aplurality of prestressed elevation member microstructures pivotallyinterconnected with said substrate with said pivotless compliantmicrostructure being mounted on said plurality of prestressed elevationmember microstructures.
 43. A microelectromechanical system, as claimedin claim 42, wherein: said pivotless compliant microstructure comprisesa first portion of said coupling assembly microstructure, wherein asecond portion of said coupling assembly microstructure is disposedbetween said input section of said pivotless compliant microstructureand said first load microstructure, and wherein said means fortransmitting in relation to said first condition comprises at lease onedoubly clamped beam that is attached to said second portion of saidcoupling assembly microstructure and that is anchored to said substrateon opposite sides of second portion of said coupling assemblymicrostructure.
 44. A microelectromechanical system, as claimed in claim35, wherein: said means for transmitting in relation to said secondcondition comprises said pivotless compliant microstructure beinginterconnected with said substrate at only first and second locations,wherein said pivotless compliant microstructure is pivotallyinterconnected with said substrate at said first and second locations.45. A microelectromechanical system, as claimed in claim 44, wherein:said pivotless compliant microstructure comprises a first portion ofsaid coupling assembly microstructure, wherein a second portion of saidcoupling assembly microstructure is disposed between said input sectionof said pivotless compliant microstructure and said first loadmicrostructure, and wherein said means for transmitting in relation tosaid first condition comprises at lease one doubly clamped beam that isattached to said second portion of said coupling assembly microstructureand that is anchored to said substrate on opposite sides of secondportion of said coupling assembly microstructure.
 46. Amicroelectromechanical system, as claimed in claim 35, wherein: saidmeans for transmitting in relation to said second condition comprisesfirst and second cavities formed in said substrate on opposite sides ofa reference axis that extends between said input and output sections ofsaid pivotless compliant microstructure, wherein first and secondlateral extremes of said pivotless compliant microstructure are disposedabove said first and second cavities, respectively.
 47. Amicroelectromechanical system, as claimed in claim 35, wherein: saidpivotless compliant microstructure is disposed in spaced relation tosaid substrate and is anchored to said substrate at first and secondlocations, wherein said first and second anchor locations are disposedon opposite sides of a reference axis that extends between said inputand output sections of said pivotless compliant microstructure and thatdefines a longitudinal dimension whereby said first and second anchorlocations are laterally spaced, wherein said pivotless compliantmicrostructure further comprises first and second lateral extremes thatare disposed on opposite sides of said reference axis, wherein saidfirst and second anchor locations are disposed at a longitudinalposition from said output section that is at least as great as alongitudinal position of said first and second lateral extremes, whereinsaid means for transmitting in relation to said second conditioncomprises a position of said first and second anchor locations relativeto said first and second lateral extremes.
 48. A microelectromechanicalsystem, as claimed in claim 35, wherein: said means for transmitting inrelation to said second condition comprises a cavity in said substrate,wherein at least a substantial portion of said pivotless compliantmicrostructure is disposed within said cavity.
 49. Amicroelectromechanical system, comprising: a substrate; a first loadmicrostructure movably interconnected with said substrate for movementalong a first path that is at least generally parallel with saidsubstrate; a second load microstructure movably interconnected with saidsubstrate; a force isolator microstructure interconnected with saidsubstrate; a first coupling microstructure allowing a first force to betransmitted between said force isolator microstructure and said firstload microstructure, wherein said first force is in a direction that isat least generally collinear with a motion of said first loadmicrostructure along said first path; and a second couplingmicrostructure allowing a second force to be transmitted between saidforce isolator microstructure and said second load microstructure,wherein said first and second forces are non-collinear, wherein a thirdforce exerted on said force isolator microstructure is a resultant ofsaid first and second forces, wherein said force isolator microstructureis configured such that no surfaces of said force isolatormicrostructure are deflected into contact with any other portion of saidmicroelectromechanical system during normal operation of saidmicroelectromechanical system and including upon exposure to said thirdforce.
 50. A microelectromechanical system, as claimed in claim 49,wherein: said force isolator microstructure comprises means forredirecting at least a portion of said second force so as to be appliedto said first load microstructure in a manner so as to be at leastgenerally collinear with said first force.
 51. A microelectromechanicalsystem, as claimed in claim 49, wherein: said force isolatormicrostructure comprises means for restraining an application of avertical force component from said second force to said first loadmicrostructure.
 52. A microelectromechanical system, as claimed in claim49, wherein: said force isolator microstructure is selected from thegroup consisting essentially of a pivotless compliant microstructure, aspacing between at least a portion of said pivotless compliantmicrostructure and said substrate, how said pivotless compliantmicrostructure is interconnected with said substrate, how said secondcoupling assembly microstructure interconnects with said pivotlesscompliant microstructure, at least one doubly clamped beam that isattached to said first coupling assembly microstructure and anchored tosaid substrate on opposite sides of said first coupling assemblymicrostructure, and any combination thereof.
 53. A method for operatinga microelectromechanical system that comprises first and second loadmicrostructures and a coupling assembly microstructure that is disposedbetween and that interconnects said first and second loadmicrostructures, said method comprising the steps of: moving said firstload microstructure relative to said substrate at least generally alonga first path; moving said second load microstructure relative to saidsubstrate at least substantially along a second path, wherein saidmoving said second load microstructure step exerts a force on saidcoupling microstructure having a vector that is disposed innon-collinear relation to said first path; configuring saidmicroelectromechanical system to preclude any portion of said couplingmicrostructure from deflecting into contact with any other portion ofsaid microelectromechanical system due to said moving said second loadmicrostructure step; and redirecting said force prior to reaching saidfirst load microstructure so as be at least substantially directed alongsaid first path.
 54. A method, as claimed in claim 53, wherein: saidmoving said first load microstructure step comprises moving said firstload microstructure relative to said substrate along an at leastsubstantially linear said first path.
 55. A method, as claimed in claim53, wherein: said moving said first load microstructure step comprisesmoving said first load microstructure relative to said substrate in atleast substantially parallel relation to said substrate.
 56. A method,as claimed in claim 53, wherein: said moving said second loadmicrostructure step is responsive to said moving said first loadmicrostructure step.
 57. A method, as claimed in claim 53, wherein: saidmoving said first load microstructure step and said moving said secondload microstructure step are each executed at a first elevation withinsaid microelectromechanical system.
 58. A method, as claimed in claim57, wherein: said moving said first load microstructure step and saidmoving said second load microstructure step are executed along at leastgenerally parallel paths.
 59. A method, as claimed in claim 53, wherein:said moving said first load microstructure step is executed at a firstelevation within said microelectromechanical system and said moving saidsecond load microstructure step is executed a second elevation withinsaid microelectromechanical system that is different from said firstelevation.
 60. A method, as claimed in claim 53, wherein: said movingsaid second load microstructure step comprises moving said second loadmicrostructure along an at least substantially linear path.
 61. Amethod, as claimed in claim 53, wherein: said moving said second loadmicrostructure step comprises pivoting said second load microstructurerelative to said substrate.
 62. A method, as claimed in claim 53,wherein: said moving said second load microstructure step comprisesmoving said second load microstructure along an at least generallyarcuate path.
 63. A method, as claimed in claim 53, wherein: saidcoupling assembly microstructure comprises a pivotless compliantmicrostructure interconnected with said substrate and comprising inputand output sections that are both movable relative to said substratewithin a lateral dimension that is at least generally parallel with saidsubstrate, wherein said second load microstructure is interconnectedwith said output section of said pivotless compliant microstructure andsaid input section of said pivotless compliant microstructure isinterconnected with said first load microstructure, wherein said movingsaid first load microstructure step displaces said input section of saidpivotless compliant microstructure a first distance within said lateraldimension, and that in turn displaces said output section of said firstdisplacement multiplier microstructure a second distance in said lateraldimension, wherein said first and second distances are selected from thegroup consisting of equal and unequal magnitudes.
 64. A method, asclaimed in claim 63, wherein: said configuring step comprises selectinga manner of interconnecting said second load microstructure with saidpivotless compliant microstructure.
 65. A method, as claimed in claim63, wherein: said configuring step comprises mounting said pivotlesscompliant microstructure on a rigid frame that is pivotallyinterconnected with said substrate.
 66. A method, as claimed in claim63, wherein: said configuring step comprises mounting said pivotlesscompliant microstructure on a plurality of pre-stressed elevation membermicrostructures.
 67. A method, as claimed in claim 63, wherein: saidconfiguring step comprises mounting said pivotless compliantmicrostructure on a plurality of compliant members that are pivotallyinterconnected with said substrate and that are at least generallyarcuately shaped extending away from said substrate.
 68. A method, asclaimed in claim 63, wherein: said configuring step comprises pivotallyinterconnecting said pivotless compliant microstructure with saidsubstrate.
 69. A method, as claimed in claim 63, wherein: saidconfiguring step comprises providing a sufficient spacing between atleast the portion of said pivotless compliant microstructure and saidsubstrate.
 70. A method, as claimed in claim 63, wherein: saidconfiguring step comprises providing a sufficient spacing between anentirety of said pivotless compliant microstructure and said substrate.71. A method, as claimed in claim 63, wherein: said configuring stepcomprises selecting appropriate anchor locations for said pivotlesscompliant microstructure to said substrate.
 72. A method, as claimed inclaim 53, wherein: said redirecting step comprises disposing a pivotlesscompliant microstructure between said first load microstructure and saidsecond load microstructure, wherein said pivotless compliantmicrostructure is part of said coupling assembly microstructure.
 73. Amethod, as claimed in claim 53, wherein: said redirecting step comprisesrestraining motion of at least the portion of said coupling assemblymicrostructure away from said substrate.
 74. A method, as claimed inclaim 73, wherein: said restraining step comprises using at least onedoubly clamped beam that is attached to a first part of said couplingassembly microstructure and that is anchored to said substrate onopposite sides of said first part of said coupling assemblymicrostructure.